Exposure head, exposure apparatus, and application thereof

ABSTRACT

In an exposure apparatus of the invention, for a spatial light modulator, each of a plurality of pixel portions fewer than the total number of the pixel portions is controlled with a control signal generated according to exposure information. Namely, a part of the pixel portions is controlled without controlling a whole of the pixel portions on the substrate. Thus, the number of pixels in the pixel portions is decreased, and transfer time of the control signal becomes short. This enables modulation speed of the laser beam to be increased and the high-speed exposure to be performed. An incorporated laser light source, in which the laser beams are incorporated and struck on the optical fiber, is preferable to the laser device. By adopting the incorporated laser light source, high brightness and high output can be obtained, and it is preferable to the exposure of the spatial light modulator. Since the fiber array is obtained with few optical fibers, it is low cost. Since the number of optical fibers is few, the light-emitting region is further decreased when the optical fibers are arrayed.

This is a divisional of application Ser. No. 10/409,686 filed Apr. 9,2003 now U.S. Pat. No. 6,894,712.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exposure head, an exposureapparatus, and application thereof, particularly relates to the exposurehead which exposes a photosensitive material with a light beam modulatedby a spatial light modulator according to image information, theexposure apparatus which includes the exposure head, and a rapidprototyping apparatus, a stacking rapid prototyping apparatus, and ableaching apparatus to which the exposure apparatus is applied, and aforming method of a micro channel which utilizes the exposure apparatus.

2. Description of the Related Art

Conventionally, there has been proposed various kinds of the exposureapparatus which performs an image exposure with the light beam modulatedaccording to the image data, utilizing the spatial light modulator suchas a digital micro-mirror device (DMD).

For example, DMD is a mirror device in which many micro-mirrors whosereflection plane angle is changeable according to a control signal aretwo-dimensionally arranged on a semiconductor substrate such as silicon,as shown in FIG. 15A, the exposure apparatus using DMD includes a lightsource 1 which applies a laser beam, a lens system 2 which collimatesthe laser beam emitted from the light source 1, DMD 3 which is arrangedat an almost focal point of the lens system 2, and lens systems 4 and 6which focuses the laser beam reflected with DMD 3 on a scanning surface5.

In the above-described exposure apparatus, each of micro-mirrors in DMD3 is on and off-controlled to modulate the laser beam by a controldevice which is not shown with a control signal generated according tothe image data or the like, the image exposure is performed with themodulated laser beam.

However, DMD which is usually used is formed in such a manner that about800 micro-mirrors in a main scanning direction and about 600micro-mirrors in a sub-scanning direction are two-dimensionally arrangedon the substrate, it takes 10 to 200 μsec to modulate the laser beam byone micro-mirror corresponding to one pixel.

Therefore, for example, in the case that plural exposure heads arrangedin the main scanning direction is continuously moved in the sub-scanningdirection, the modulation is performed at 200 μsec per one main scanningline, while the exposure head is moved by 2 μm in the sub-scanningdirection, it takes about 50 seconds to expose an area of 50 mm². Thatis to say, there is a problem that modulation speed of DMD is slow, sothat it is difficult to perform the high-speed exposure in the exposurehead using DMD as the spatial light modulator.

The invention has been done in order to solve the above-describedproblem, it is a first object of the invention to provide the exposurehead and the exposure apparatus, in which the modulation speed of thespatial light modulator is increased and the high-speed exposure can beperformed.

In recent years, as three-dimensional CAD (Computer Aided Design) systemis widely spread, the rapid prototyping system is being utilized. Therapid prototyping system shapes a three-dimensional model in such amanner that a three-dimensional shape is formed in a virtual space on acomputer with the three-dimensional CAD and three-dimensional model isshaped on the basis of CAD data by exposing a photo-curable resin withthe light beam. In the rapid prototyping system, on the computer, CADdata is sliced at a given interval to generate a plurality of sectiondata, a surface of the liquid photo-curable resin is scanned on thebasis of each section data with the laser beam and cured in laminar, thecured resin layer is stacked in order to shape the three-dimensionalmodel. In the rapid prototyping method, a free liquid surface method iswidely known, in which the photo-curable resin is reserved in anopen-top type of tank, while a shaping table arranged near the liquidsurface of the photo-curable resin is sequentially descended from a freeliquid surface, the cured resin layer is stacked.

Conventionally, in the rapid prototyping apparatus used for this rapidprototyping system, as described in “HIKARIZOUKEI SISUTEMU NO KISO,GENJOU, MONDAITEN, KATAGIJUTU” MARUYA, Yoji, Vol. 7, No. 10, pp. 18–23(1992), there are the rapid prototyping apparatus adopting a laserplotter method scanning and the rapid prototyping apparatus adoptingmovable mirror method scanning.

FIG. 30 shows the rapid prototyping apparatus adopting the laser plottermethod. In the apparatus, the laser beam oscillated from a laser lightsource 250 passes an optical fiber 254 including a shutter 252 andreaches an XY plotter 256, and the laser beam is applied from the XYplotter 256 to a liquid surface 266 of a photo-curable resin 262 in avessel 260. Positions in an X-direction and a Y-direction of the XYplotter 256 are controlled with an XY positioning mechanism 258including an X-positioning mechanism 258 a and a Y-positioning mechanism258 b. Accordingly, while the XY plotter 256 is moved in the X-directionand Y-direction, the laser beam applied from the XY plotter 256 with theshutter 252 is on and off-controlled according to the section data,which allows the photo-curable resin 262 in a given portion of theliquid surface 266 to be cured.

However, in the rapid prototyping apparatus adopting the laser plottermethod, there is the problem that shutter speed and moving speed of theplotter are limited and plenty time is required for the shaping.

FIG. 31 shows the rapid prototyping apparatus of the movable mirrormethod using a conventional galvanometer mirror. In the apparatus, thelaser beam 270 is reflected with an X-axis rotating mirror 272 and aY-axis rotating mirror 274 to be applied to the photo-curable resin 262.The X-axis rotating mirror 272 controls an irradiating position in theX-direction by rotating about a Z-axis, and the Y-axis rotating mirror274 controls the irradiating position in the Y-direction by rotatingabout the X-axis. In the movable mirror method, the scanning speed canbe increased compared with the laser plotter method.

However, in the rapid prototyping apparatus adopting the movable mirrormethod, since the scanning is performed with a micro laser spot, theshaping requires for long hours, for example, even in the case that thefast scanning of 2 to 12 m/s is performed, it takes 8 to 24 hours toshape the three-dimensional model of about 10 centimeter cubic. Theirradiation area of the laser beam 270 is limited, because the laserbeam 270 is only reflected when the laser beam 270 is incident to theY-axis rotating mirror 274 at a given range of the incident angle. Inorder to extend the irradiation range, when the Y-axis rotating mirror274 is arranged at a higher position where the Y-axis rotating mirror274 is far away from the photo-curable resin 262, there is the problemthat a diameter of the laser spot is increased, positioning accuracy isworsened, and shaping accuracy is decreased. When rotating angle of theY-axis rotating mirror 274 is increased, though the irradiation area isenlarged, the positioning accuracy is worsened in similar way, and a pincushion error is increased. Furthermore, in the rapid prototypingapparatus using the galvanometer mirror, there is the problem thatadjustment of the optical system is complicated and upsizing of theapparatus occurs because of the complicated optical system.

In rapid prototyping apparatuses of both methods, an ultraviolet laserbeam having high output is used as the laser beam. In the related art, agas laser such as an argon gas laser or a solid state laser generated byTHG (Third Harmonic Wave) is usually used. However, in the gas laser,maintenance such as tube exchange is troublesome, incidental facilitiessuch as cooling chiller which is expensive and raises the price of therapid prototyping apparatus are required, and the apparatus is upsized.THG solid state gas laser is pulse operation of Q switch, repeatingspeed is slow and it is improper for the high-speed exposure. Since THGlight is used, wavelength transformation efficiency is bad and highoutput is impossible. In addition, high output laser must be used as theexciting laser diode, it is very high cost.

In order to solve the problem, in Japanese Patent Application Laid-Open(JP-A) No. 11-138645, there is proposed the rapid prototyping apparatusin which a plurality of light sources which can irradiates the exposureregion with larger spot size than single pixel are provided and thepixel is multi-exposed with the plurality of light sources. In theapparatus, since the pixel is exposed in multiple with the plurality oflight sources, the output of each light source may be small, whichenables cheap light emitting diode (LED) to use as the light source.

However, in the rapid prototyping apparatus described in JP-A No.11-138645, there is the problem that, since the spot size of each lightsource is larger than the single pixel, the apparatus can not be usedfor the fine shaping, and, since the pixel is exposed in multiple withthe plurality of light sources, there are many needless operations andthe shaping requires long hours. Also, there is the problem that theexposure portion is upsized by increasing the number of light sources.Further, there is a fear that sufficient resolution is not obtained evenif the multiple exposures are performed by the output light intensity(quantity) of LED.

The invention has been done in order to solve the above-describedproblem, and it is a second object of the invention to provide the rapidprototyping apparatus which can perform the high-speed shaping. It is athird object of the invention to provide the rapid prototyping apparatuswhich can perform the fine shaping.

A powder sintering-stacking rapid prototyping apparatus is known as therapid prototyping system which is developed after the stacking rapidprototyping apparatus using the photo-curable resin and widely usedcurrently. In the powder sintering-stacking rapid prototyping apparatus,the surface of the powder body is scanned with the laser beam on thebasis of the section data of the three-dimensional model which isgenerated on the computer. The powder body is cured in such a mannerthat the powder body is sequentially melted and sintered with thescanning of the laser beam, and the curing process is repeated. Thethree-dimensional model including the stacked sintered body is shaped byrepeating the process.

In the stacking rapid prototyping apparatus adopting the sintering,there is an advantage that various kinds of materials can be selected,not only a ductile functional evaluation model or a precise castingpattern and a matrix but also a metal mold or a metallic part can bedirectly produced, and application field is wide. Further, in thestacking rapid prototyping apparatus, the apparatus price is moderatecompared with the rapid prototyping apparatus, and forming speed isrelatively fast, so that the application is fixing for confirmation of adesign model.

However, even in the stacking rapid prototyping apparatus adopting thesintering, the movable mirror method such as the galvanometer mirror isadopted, and the gas laser such as CO₂ laser (wavelength is 10.6 μm) andthe solid state laser such as YAG laser (wavelength is 1.06 μm), whichoutput the infrared having the high output power, are used as the lightsource. Therefore, the same problem as that of the above-described rapidprototyping apparatus occurs when these units is used. Since the beamspot is large, the resolution is low. Further, since the light source islong wavelength, a spread angle of the beam is large, so that sufficientfocal depth can not be obtained.

The invention has been done in order to solve the above-describedproblem, and it is a fourth object of the invention to provide the rapidprototyping apparatus which can perform the high-speed shaping. It is afifth object of the invention to provide the rapid prototyping apparatuswhich can perform the fine shaping.

Recently, a device technology called “lob on chip” (Laboratory on Chip),in which a system performing mixing, reaction, separation, and detectionof a solution is integrated on a glass plate of several centimeterssquare, is actively investigated by adopting a micromachiningtechnology. The lob on chip is also called as micro TAS (Micro TotalAnalysis System), micro reactor, or the like according to the integratedsystem.

Usually the lob on chip includes the micro channel whose channel widthranges from several tens μm to several hundreds μm, which is formed inthe substrate having a thickness of about 1 mm. The mixing of thesolution and the like is performed in the micro channel. Since relativearea is enlarged in the micro channel, the mixing or reaction of thesolution can be efficiently performed such that the solutions whichhardly react with each other can react by a size effect and thesolutions which are hardly mixed with each other can be mixed. Bysetting the channel width of the micro channel to the range form 10 μmto 50 μm, channel resistance can be relatively decreased and the goodsize effect can be obtained. Since the shape of the micro channelinfluences solution delivery characteristics, it is preferable that themicro channel has smooth wall surface and is produced finely.

Conventionally, the micro channel of the lob on chip is formed with asemiconductor processing technique such that the surface of thesubstrate is coated with a resist film, the resist film is patterned byphotolithography with ultraviolet ray or electron beam, and then thesubstrate is etched by using the patterned resist film as a mask. Thephotolithography is performed with a contact aligner which is used inthe semiconductor manufacturing process. Its exposure method is ananalog exposure method which uses a mask aligner, for example, it isdifficult to perform the fast exposure of a large area of 1 squaremeter.

In the forming method of the micro channel of the related art, since thepatterning is performed with the mask exposure, there is the problemthat the thickness of the photoresist film is limited, and it isdifficult to finely form the micro channel. That is to say, when thephotoresist film is thin, the photoresist film is easily side-etched inetching the substrate, preparation accuracy of the channel width isdecreased, and sufficient channel depth can not be achieved.

In the mask exposure, since a precise glass mask or the like is requiredin each pattern, there is the product that cost is increased, it isdifficult to enlarge the area, and it is not prefer to limitedproduction of a wide variety of products.

On the other hand, though it is thought that the photolithographyprocess is performed with a digital exposure method, the conventionaldigital exposure apparatus using the ultraviolet ray performs scanningexposure with the single beam, so that the exposure time is too long. Inparticular, in the case of the fine exposure in which the beam diameteris not more than 10 μm and addressability is about 1 μm, there is theproblem that the exposure time is too long.

The invention has been done in order to solve the above-describedproblem, and it is a sixth object of the invention to provide theforming method of the micro channel which can finely form the microchannel at high speed. It is a seventh object of the invention toprovide the forming method of the micro channel which can form the microchannel having an arbitrary pattern at low cost.

In dyeing of cloth product, bleaching in which color substance includedin the cloth is dissolved and removed with oxidation or reductiontreatment is performed prior to the dyeing. Though the color substanceincludes a conjugated double bond involving coloring in its structure,the conjugated system of the color substance is broken by the oxidationor reduction treatment, as a result, the cloth is bleached. A chlorinebleaching agent such as sodium hypochlorite, hydrogen peroxide, and thelike are used as an oxidation bleaching agent. Hydrosulfite and the likeare used as a reduction bleaching agent.

Conventionally, the above-described bleaching is usually performed byboiling the cloth product for long time in a water solution containingthe dense bleaching agent, however, there is the problem that it isnecessary that the water having large heat capacity is heated to nearthe boiling point, the energy efficiency is bad, embrittlement andhardening of the cloth, which are caused by interaction between the heatand the chemicals, are generated.

In recent years, research on the bleaching technique which does not usethe chlorine bleaching agent having a large load to the environment isactively being done. For example, in JP-A No. 11-43861, there isdisclosed a technique in which cotton cloth impregnated with sodiumboron hydroxide is pulse-irradiated with the ultraviolet laser tobleach. Though reduction power of the sodium boron hydroxide, which isused as the bleaching agent, is weak, the color substance is activatedwith the laser irradiation to react easily with the bleaching agent.According to this technique, not only the bleaching can be performedwithout using the chlorine bleaching agent, but also the bleaching canbe performed at lower temperature, so that the processing time can bereduced. Due to the bleaching at lower temperature, damage of the clothis also reduced.

In the bleaching method, the laser device having the high energy densityis required, and excimer laser which can obtain the high output in theultraviolet region is used. Since the output of the laser diode whichoscillates in the ultraviolet wave range is generally small, when thelaser diode is used, the plurality of laser diodes are integrated andused.

However, the energy efficiency of the excimer laser is as low as only3%, and energy consumption is increased in the bleaching method usingthe excimer laser, so that the bleaching method is notenvironment-friendly. In the excimer laser, since repeating frequency ofthe pulse driving is as low as 300 Hz, the productivity is low. Further,there is also the problem that life of the laser tube or the laser gasis as low as about 1×10⁷ shots, the maintenance cost is high, theapparatus is upsized, high-bright laser beam is not obtained, and pulsedriving is difficult for the excimer laser.

Conventionally, the laser diode which oscillates in the ultraviolet waverange has not been realized, the specific construction of the laserdiode is not described in JP-A No. 11-43861. In addition, though it isdifficult to manufacture the laser diode having the short wavelengthwith high yield, in JP-A No. 11-43861, there is no description about thespecific construction in which the plurality of laser diodes whichoscillates in ultraviolet wave range are integrated and the lightdensity of 10000 mJ/cm² is realized, and actually it is difficult toobtain the high output light source in which the laser diode oscillatingin the ultraviolet wave range is used.

The invention has been done in order to solve the above-describedproblem of the related art, and it is an eighth object of the inventionto provide the bleaching apparatus in which the bleaching can beperformed with high energy density by applying the laser beam having theshort pulse. It is a ninth object of the invention to provide thebleaching apparatus in which the energy efficiency is high and the fastand low-cost bleaching can be performed.

SUMMARY OF THE INVENTION

In order to achieve the above-described first object of the presentinvention, there is provided an exposure head, wherein the exposure headwhich is relatively moved in a direction crossed at right angles with apredetermined direction for an exposure surface, which comprises a laserdevice which irradiates a laser beam, a spatial light modulator in whichmany pixel portions, in which a light modulation state is changedaccording to each control signal, are arranged two-dimensionally on asubstrate and which modulates the laser beam irradiated from the laserdevice, control means which controls each of the plurality of pixelportions fewer than the total number of the pixel portions arranged onthe substrate with the control signal generated according to exposureinformation, and an optical system which focuses the laser beammodulated with each pixel portion on the exposure surface.

An exposure apparatus of the invention is characterized by comprisingthe exposure head of the invention and moving means which relativelymoves the exposure head in a direction crossed with a predetermineddirection for the exposure surface. The exposure apparatus can be alsoformed as a multi-head type of exposure apparatus including theplurality of exposure heads.

In the exposure head and the exposure apparatus of the invention, forthe spatial light modulator, each of the plurality of pixel portionsfewer than the total number of the pixel portions is controlled with thecontrol signal generated according to exposure information. That is tosay, a part of the pixel portions is controlled without controlling awhole of the pixel portions arranged on the substrate. Consequently, thenumber of pixels in the pixel portions is decreased, and transfer timeof the control signal becomes short compared with the case that thecontrol signals of the whole of the pixel portions are transferred. Thisenables the modulation speed of the laser beam to be increased and thehigh-speed exposure to be performed.

The exposure head moving is relatively moved in a direction crossed atright angles with a predetermined direction for the exposure surface,and it is preferable that the pixel portion controlled with the controlmeans is the pixel portion which is included in a region in which alength in a direction corresponding to the predetermined direction islonger than length in a direction crossed with the predetermineddirection. The number of using exposure heads can be decreased by usingthe pixel portion having the long region in the direction crossed withthe moving direction (sub-scanning direction) of the exposure head.

In the exposure head, the laser device may include a plurality of fiberlight sources which irradiates the laser beam incident from an incidentend of the optical fiber from an outgoing end of the optical fiber, andincludes a fiber array light source in which each light-emitting pointat the outgoing end of the plurality of fiber light source is arrangedin the shape of an array or a bundle light source in which eachlight-emitting point at the outgoing end is arranged in the shape of abundle. For the above-described optical fiber, it is preferable to usethe optical fiber, in which the core diameter is uniform and the claddiameter of the outgoing end is smaller that that of the incident end.

The incorporated laser light source, in which the laser beams areincorporated and struck on the optical fiber, is preferable to eachfiber light source constituting the fiber array light source or thefiber bundle light source. By adopting the incorporated laser lightsource, high brightness and high output can be obtained, and it ispreferable to the exposure of the spatial light modulator. Particularly,in the laser diode having the oscillating wavelength of 350 nm to 450nm, though it is difficult to obtain the high output with singleelement, incorporation can realize the high output.

Since the optical fiber array is obtained with few optical fiberscompared with the related art, it is low cost. Furthermore, since thenumber of optical fibers is few, the light-emitting region is furtherdecreased when the optical fibers are arrayed (or the brightness isfurther increased).

For example, the fiber light source can be include a plurality of laserdiodes, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam on the incident end of the opticalfiber.

The fiber light source may include a multi-cavity laser having aplurality of light-emitting points arranged in a predetermineddirection, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality oflight-emitting points and focuses the condensed beam on the incident endof the optical fiber. Further, the laser beam emitted from each of thelight-emitting points of the plurality of multi-cavity lasers may becondensed and coupled to one optical fiber.

A micro-mirror device in which many micro-mirrors whose angle of areflection plane is changeable according to each control signal areformed to be arranged two-dimensionally or a liquid crystal shutterarray in which many liquid crystal cells which can shut transmittedlight according to each control signal are formed to be arrangedtwo-dimensionally may be used as the spatial light modulator.

It is preferable that a collimator lens which parallels the laser beam(light flux) from the laser device and an optical system for correctinglight intensity (quantity) distribution are arranged, the optical systemfor correcting light intensity distribution changes a light flux widthat each outgoing position so that a ratio of the light flux width of aperipheral portion to the light flux width of a central portion near anoptical axis is decreased on an outgoing side compared with an incidentside, and corrects the light intensity distribution of the laser beamparalleled with the collimator lens so as to be substantially uniformedat an irradiated surface of the spatial light modulator are arrangedbetween the laser device and the spatial light modulator.

According to the optical system for correcting light intensitydistribution, for example, though the light has the same light fluxwidth on the incident side, the light flux width of the central portionis increased on the outgoing side compared with the peripheral portion,on the contrary, the light flux width of the peripheral portion isdecreased compared with the central portion. Thus, the light flux in thecentral portion can be utilized to the peripheral portion, so that thespatial light modulator can be irradiated with the light whose lightintensity distribution is substantially uniformed without reducing thelight utilization efficiency as a whole. Consequently, the unevenexposure never occurs and the high-quality exposure can be performed.

In the related art, a gas laser such as an argon gas laser or a solidstate laser generated by THG (Third Harmonic Wave) is usually used asthe exposure apparatus (ultraviolet exposure apparatus) which exposesthe photosensitive material with the laser beam of the ultraviolet waverange, however, there is the problem that the apparatus is large and theexposure speed is slow. In the exposure apparatus of the invention canbe used as the ultraviolet exposure apparatus by using a GaN (galliumnitride) laser diode having the wavelength of 350 nm to 450 nm.According to the ultraviolet exposure apparatus, miniaturization of theapparatus and the cost reduction can be achieved and the high-speedexposure can be performed, compared with the apparatus of the relatedart.

In order to achieve the above-described second object of the invention,there is provided a rapid prototyping apparatus, wherein the rapidprototyping apparatus comprises an exposure head including a shapingtank which stores a photo-curable resin, a support which is providedelevatably in the shaping tank and supports a shaped article, a laserdevice which irradiates a laser beam, a spatial light modulator in whichmany pixel portions, in which a light modulation state is changedaccording to each control signal, are arranged two-dimensionally on asubstrate and which modulates the laser beam irradiated from the laserdevice, control means which controls each of the plural pixel portionsfewer than the total number of the pixel portions arranged on thesubstrate with the control signal generated according to exposureinformation, and an optical system which focuses the laser beammodulated in each pixel portion on a liquid surface of the photo-curableresin stored in the shaping tank, and moving means which relativelymoves the exposure head for the liquid surface of the photo-curableresin.

In the rapid prototyping apparatus of the invention, the liquid surfaceof the photo-curable resin stored in the shaping tank is scanned andexposed in such a manner that the exposure head is relatively moved forthe liquid surface of the photo-curable resin with the moving means,while the laser beam modulated with each pixel portion of the spatiallight modulation in the exposure head is focused on the liquid surfaceof the photo-curable resin stored in the shaping tank. The exposed resinis cured to form the cured resin layer. After one layer of the curedresin layer is formed, the support which is provided in the shaping tankand supports the shaped article is descended to form the new resinsurface, and then the next cured resin layer is formed in the same way.Thus, the curing of the resin and the descent of the support arerepeated, the cured resin layer is stacked in order, and thethree-dimensional model is shaped.

In the rapid prototyping apparatus of the invention, for the spatiallight modulator of the exposure head, each of the plurality of pixelportions fewer than the total number of the pixel portions is controlledwith the control signal generated according to exposure information.That is to say, a part of the pixel portions is controlled withoutcontrolling a whole of the pixel portions arranged on the substrate.Consequently, the number of pixels in the pixel portions is decreased,and transfer time of the control signal becomes short compared with thecase that the control signals of the whole of the pixel portions aretransferred. This enables the modulation speed of the laser beam to beincreased and the high-speed shaping to be performed.

In the rapid prototyping apparatus, it is preferable that the pixelportion controlled with the control means is the pixel portion which isincluded in a region in which a length in a direction corresponding tothe predetermined direction is longer than length in a direction crossedwith the predetermined direction. The number of using exposure heads canbe decreased by using the pixel portion having the long region in thearray direction of the light-emitting points of the exposure device.

In the rapid prototyping apparatus, the laser device may include aplurality of fiber light sources which irradiates the laser beamincident from an incident end of the optical fiber from an outgoing endof the optical fiber, and includes a fiber array light source in whicheach light-emitting point at the outgoing end of the plurality of fiberlight source is arranged in the shape of a one-dimensional ortwo-dimensional array. The laser device may also include a fiber bundlelight source in which each light-emitting point at the outgoing end ofthe plurality of fiber light sources is arranged in the shape of abundle. The arraying or the bundling can increase the output. For theabove-described optical fiber, it is preferable to use the opticalfiber, in which the core diameter is uniform and the clad diameter ofthe outgoing end is smaller that that of the incident end.

The incorporated laser light source, in which the laser beams areincorporated and struck on the optical fiber, is preferable to eachfiber light source constituting the fiber array light source or thelike. By adopting the incorporated laser light source, high brightnessand high output can be obtained, and it is preferable to the exposure ofthe spatial light modulator. Since the optical fiber array is obtainedwith few optical fibers compared with the related art, it is low cost.Furthermore, since the number of optical fibers is few, thelight-emitting region is further decreased when the optical fibers arearrayed (or the brightness is further increased). By using the fiberhaving the smaller clad diameter, the light-emitting area is furtherdecreased when the optical fibers are arrayed, so that brightness can befurther increased. Even in the case that the spatial light modulator ispartially used, by using the high-bright fiber array light source orfiber bundle light source, the focal depth of the focusing beam whichhas passed through the spatial light modulator can be taken deeplybecause irradiation NA of the spatial light modulator is decreased, andthe used portion can be efficiently irradiated with the laser beam andthe laser beam can be irradiated with high light density. Consequently,the fine exposure and shaping can be performed at high speed. Forexample, the shaping having the fine shape of 1 μm order can beperformed.

For example, the fiber light source can be include a plurality of laserdiodes, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam on the incident end of the opticalfiber. The fiber light source may include a multi-cavity laser having aplurality of light-emitting points arranged in a predetermineddirection, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality oflight-emitting points and focuses the condensed beam on the incident endof the optical fiber. Further, the laser beam emitted from each of thelight-emitting points of the plurality of multi-cavity lasers may becondensed and coupled to one optical fiber.

A digital micro-mirror device (DMD) an which many micro-mirrors whoseangle of a reflection plane is changeable according to each controlsignal are formed to be arranged two-dimensionally or a liquid crystalshutter array in which many liquid crystal cells which can shuttransmitted light according to each control signal are formed to bearranged two-dimensionally may be used as the spatial light modulatorused for the above-described rapid prototyping apparatus. Power isdispersed and heat deformation can be prevented in such a manner thatthe exposure is performed with multi-channel by using the spatial lightmodulator including the many pixel portions like DMD.

It is preferable that the laser device used for the rapid prototypingapparatus irradiates the shaped article with the laser beam whosewavelength ranges from 350 to 450 nm. By using of GaN laser diode as alaser diode, the laser device can irradiate a laser beam whosewavelength ranges from 350 to 450 nm. Using of the laser beam whosewavelength ranges from 350 to 450 nm causes the light absorption factorof the photo-curable resin to largely increase, compared with the casein which the laser beam having the infrared wave range. Since the laserbeam of the wavelength of 350 to 450 nm is short, photon energy is largeand it is easy to transform the laser beam into the thermal energy. Thelaser beam of the wavelength of 350 to 450 nm has large light absorptionfactor, and the transformation into the thermal energy is easy, so thatthe curing of the photo-curable resin, i.e., the shaping can beperformed at high speed. It is preferable that the wave range of thelaser beam ranges from 350 to 420 nm. The wavelength of 405 nm isparticularly preferable, considering that the low-cost GaN laser diodeis used.

The rapid prototyping apparatus can be formed as a multi-head type ofrapid prototyping apparatus, which includes the plurality of exposureheads. The multi-head can achieve further high-speed shaping.

In order to achieve the above-described fourth object of the invention,there is provided a stacking rapid prototyping apparatus, wherein therapid prototyping apparatus comprises an exposure head including ashaping tank which stores a powder sintered with light irradiation, asupport which is provided elevatably in the shaping tank and supports ashaped article, a laser device which irradiates a laser beam, a spatiallight modulator in which many pixel portions, in which a lightmodulation state is changed according to each control signal, arearranged two-dimensionally on a substrate and which modulates the laserbeam irradiated from the laser device, control means which controls eachof the plural pixel portions fewer than the total number of the pixelportions arranged on the substrate with the control signal generatedaccording to exposure information, and an optical system which focusesthe laser beam modulated in each pixel portion on a surface of thepowder stored in the shaping tank; and moving means which relativelymoves the exposure head for the surface of the powder.

In the stacking rapid prototyping apparatus of the invention, thesurface of the powder stored in the shaping tank is scanned and exposedin such a manner that the exposure head is relatively moved for thesurface of the powder with the moving means, while the laser beammodulated with each pixel portion of the spatial light modulation in theexposure head is focused on the surface of the powder stored in theshaping tank. The exposed powder is sintered and cured to form thesintered layer. After one layer of the sintered layer is formed, thesupport which is provided in the shaping tank and supports the shapedarticle is descended to form the new powder surface, and then the nextsintered layer is formed in the same way. Thus, the sintering and thedescent of the support are repeated, the sintered layer is stacked inorder, and the three-dimensional model is shaped.

In the stacking rapid prototyping apparatus of the invention, for thespatial light modulator of the exposure head, each of the plurality ofpixel portions fewer than the total number of the pixel portions iscontrolled with the control signal generated according to exposureinformation. That is to say, a part of the pixel portions is controlledwithout controlling a whole of the pixel portions arranged on thesubstrate. Consequently, the number of pixels in the pixel portions isdecreased, and transfer time of the control signal becomes shortcompared with the case that the control signals of the whole of thepixel portions are transferred. This enables the modulation speed of thelaser beam to be increased and the high-speed shaping to be performed.

In the stacking rapid prototyping apparatus, it is preferable that thepixel portion controlled with the control means is the pixel portionwhich is included in a region in which a length in a directioncorresponding to the predetermined direction is longer than length in adirection crossed with the predetermined direction. The number of usingexposure heads can be decreased by using the pixel portion having thelong region in the array direction of the light-emitting points of theexposure device.

In the stacking rapid prototyping apparatus, the laser device mayinclude a plurality of fiber light sources which irradiates the laserbeam incident from an incident end of the optical fiber from an outgoingend of the optical fiber, and includes a fiber array light source inwhich each light-emitting point at the outgoing end of the plurality offiber light source is arranged in the shape of a one-dimensional ortwo-dimensional array. The laser device may also include a fiber bundlelight source in which each light-emitting point at the outgoing end isarranged in the shape of a bundle. The arraying or the bundling canincrease the output. For the above-described optical fiber, it ispreferable to use the optical fiber, in which the core diameter isuniform and the clad diameter of the outgoing end is smaller than thatof the incident end.

The incorporated laser light source, in which the laser beams areincorporated and struck on the optical fiber, is preferable to eachfiber light source constituting the fiber array light source or thelike. By adopting the incorporated laser light source, high brightnessand high output can be obtained, and it is preferable to the exposure ofthe spatial light modulator. Since light output is obtained with fewoptical fibers compared with the related art, it is low cost.Furthermore, since the number of optical fibers is few, thelight-emitting region is further decreased when the optical fibers arearrayed (or the brightness is further increased). By using the fiberhaving the smaller clad diameter, the light-emitting area is furtherdecreased when the optical fibers are arrayed, so that brightness can befurther increased. Even in the case that the spatial light modulator ispartially used, by using the high-bright fiber array light source orfiber bundle light source, the focal depth of the focusing beam whichhas passed through the spatial light modulator can be taken deeplybecause irradiation NA of the spatial light modulator is decreased, theused portion can be efficiently irradiated with the laser beam and thelaser beam can be irradiated with high light density. Consequently, thefine exposure and shaping can be performed at high speed. For example,the shaping having the fine shape of 1 μm order can be performed.

For example, the fiber light source can be include a plurality of laserdiodes, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam on the incident end of the opticalfiber. The fiber light source may include a multi-cavity laser having aplurality of light-emitting points arranged in a predetermineddirection, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality oflight-emitting points and focuses the condensed beam on the incident endof the optical fiber. Further, the laser beam emitted from each of thelight-emitting points of the plurality of multi-cavity lasers may becondensed and coupled to one optical fiber.

The digital micro-mirror device (DMD) in which many micro-mirrors whoseangle of a reflection plane is changeable according to each controlsignal are formed to be arranged two-dimensionally on a substrate or aliquid crystal shutter array in which many liquid crystal cells whichcan shut transmitted light according to each control signal are formedto be arranged two-dimensionally on a substrate may be used as thespatial light modulator used for the above-described stacking rapidprototyping apparatus. Power is dispersed and heat deformation can beprevented in such a manner that the exposure is performed withmulti-channel by using the spatial light modulator including the manypixel portions like DMD.

It is preferable that the laser device used for the rapid prototypingapparatus irradiates the shaped article with the laser beam whosewavelength ranges from 350 to 450 nm. By using of GaN laser diode as alaser diode, the laser device can irradiate a laser beam whosewavelength ranges from 350 to 450 nm. Using of the laser beam whosewavelength ranges from 350 to 450 nm causes the light absorption factorof the photo-curable resin to largely increase, compared with the casein which the laser beam having the infrared wave range. Particularly, inthe case of metal power, light absorption factor is increasedsignificantly. Since the laser beam of the wavelength of 350 to 450 nmis short, photon energy is large and it is easy to transform the laserbeam into the thermal energy. The laser beam of the wavelength of 350 to450 nm has large light absorption factor, and the transformation intothe thermal energy is easy, so that the curing of the photo-curableresin, i.e., the shaping can be performed at high speed. It ispreferable that the wave range of the laser beam ranges from 350 to 420nm. The wavelength of 405 nm is particularly preferable, consideringthat the low-cost GaN laser diode is used.

It is preferable that the laser device is pulse-driven. Since thethermal diffusion generated by the irradiating light is prevented byexposing the powder with the pulse-driven laser beam, light energy isefficiently utilized to the sintering of the light energy and thehigh-speed shaping can be performed. Since the thermal diffusion isprevented, the powder is sintered in the almost same size as theincident beam shape, so that the fine shaping can be performed withsmooth surface. Accordingly, shorter pulse width of the laser beam ispreferable, it is more preferable that the pulse width ranges from 1psec to 100 nsec, and it is further preferable that the pulse widthranges from 1 psec to 300 nsec.

The stacking rapid prototyping apparatus can be formed as a multi-headtype of raid prototyping apparatus, which includes the plurality ofexposure heads. The multi-head can achieve fiber high-speed shaping.

In order to achieve the above-described sixth and seventh objects of theinvention, there is provided a forming method of a micro channel,wherein the forming method of the micro channel compress the steps of anexposing step which exposes a resist film formed on a substrate with alaser beam having a wavelength of 350 nm to 450 nm, which is spatiallymodulated according to a forming pattern data of the micro channel, apatterning step which removes partially the resist film according to anexposure pattern and forms the resist film of a predetermined pattern,and an etching step which etches and removes the substrate from asurface to form the micro channel, by using the resist pattern of thepredetermined pattern.

Since the laser beam whose wavelength ranges from 350 nm to 450 nm isused in the forming method of the micro channel, unlike the excimerlaser, it is not necessary to use the optical system made of a specialmaterial for the ultraviolet ray, like the laser exposure apparatus ofthe visible range, the spatial light modulator such as DMD can be used.Consequently, the resist film can be exposed with the laser beam whichis modulated spatially according to forming pattern data of the microchannel. That is to say, the digital exposure of the resist film can befinely performed at high speed in an arbitrary pattern.

As described above, in the exposure process, the exposure of the resistfilm can be finely performed at high speed in an arbitrary pattern, sothat the micro channel having the arbitrary pattern can be finely formedat high speed through the following patterning process and etchingprocess. Also, because of the digital exposure, it is not necessary touse a mask in each pattern and the micro channel can be formed at lowcost.

The exposure head including the laser light source which irradiates alaser beam, the spatial light modulator in which many pixel portions, inwhich the light modulation state is changed according to each controlsignal, are arranged on the substrate and which modulates the laser beamirradiated from the laser device, and the optical system which focusesthe laser beam modulated with each pixel portion on the exposure surfacecan be used in the exposure process. The resist film formed on thesubstrate can be scanned and exposed by relatively moving the exposurehead in the direction crossed with the given surface for the exposuresurface.

In order to expose the resist film more finely, it is preferable thatthe spatial light modulator is arranged to be slightly slanted so thatthe array direction of each pixel portion of the spatial light modulatormakes a given angle θ with the direction crossed at right angles withthe sub-scanning direction and performed multiple exposure.Consequently, the fine exposure can be performed with addressability of1 μm by using the beam diameter of 10 μm. It is preferable that theoblique angle ranges from 1° to 5°.

It is more preferable that a micro-lens array including micro-lenses,which are provided corresponding to each pixel portion of the spatiallight modulator and condense the laser beam in each pixel, is arrangedon the outgoing side of the spatial light modulator. When the micro-lensarray is arranged, since the laser beam modulated with each pixelportion of the spatial light modulator is condensed corresponding toeach pixel with each micro-lens in the micro-lens array, even if theexposure area in the exposed surface is enlarged, the size of each beamspot can be contracted and the fine exposure can be performed. By usingthis contracting optical system, the fine exposure can be performed withaddressability of 0.1 μm at the beam diameter of 1 μm.

Thus, by finely exposing the resist film, very smooth wall of the microchannel can be formed and the channel resistance can be decreased toobtain good size effect.

In order to form finely the micro channel, it is preferable that thethickness of the resist film is thick. When the micro channel whosechannel width ranges from 10 μm to 50 μm is formed, it is preferablethat the thickness of the resist film ranges from 10 μm to 50 μm, and itis more preferable that the thickness of the resist film ranges from 10μm to 100 μm. In particular, it is more preferable to expose the resistfilm while the resist film is laminated in the multi-layers such as twolayers or three layers. Since the resist film is digitally exposed, thecorrection such as elongation in the exposure, development and the likecan be precisely performed with a function of digital scaling, and thepositioning of the exposure position in the first layer and that in thesecond layer or the multi-layers can be finely realized. As a result,the resist film having the thickness two times that of related art canbe finely patterned with a high aspect ratio, the fine and deep microchannel can be formed in etching process. The aspect ratio means rationof the channel depth b to the channel width a in the channel formed inthe resist film.

In the exposure process of the forming method, the resist film can beexposed with higher accuracy in such a manner that the exposure isperformed at deep focal depth with the high-bright light source. Anincorporated laser light source which incorporates a plurality laserbeams and causes the laser beams to impinge to each optical fiber ispreferable to the high-bright light source. The laser light sourcehaving the high output is required for the exposure of the thickenedresist film. In the laser diode having the oscillating wavelength of 350nm to 450 nm, though it is difficult to obtain the high output withsingle element, incorporation can realize the high output.

The incorporated laser light source may be formed with, e.g., thefollowing constructions: (1) Construction including a plurality of laserdiodes, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam to an incident end of the opticalfiber, (2) Construction including a multi-cavity laser having aplurality of light-emitting points, one optical fiber, and a condensingoptical system which condenses the laser beam emitted from each of theplurality of light-emitting points and couples the condensed beam to anincident end of the optical fiber, or (3) Construction including aplurality of multi-cavity lasers, one optical fiber, and a condensingoptical system which condenses the laser beam emitted from each of theplurality of light-emitting points of the plurality of multi-cavitylaser and couples the condensed beam to an incident end of the opticalfiber.

The fiber array light source can be formed by arranging each of thelight-emitting points at the outgoing end of the optical fiber in theincorporated laser light source in the shape of the array, or the fiberarray light source can be formed by arranging each of the light-emittingpoints in the shape of the bundle. The bundling or the arraying canfurther increase the output. In view of high brightness, it ispreferable to use the optical fiber, in which the core diameter isuniform and the clad diameter of the outgoing end is smaller than thatof the incident end.

It is preferable that the clad diameter of the outgoing end of theoptical fiber is less than 125 μm, in view of the smaller diameter ofthe light-emitting point, it is more preferable that the clad diameterof the outgoing end is not more than 80 μm, and it is particularlypreferable that the clad diameter of the outgoing end is not more than60 μm. The optical fiber in which the core diameter is uniform and theclad diameter of the outgoing end is smaller than that of the incidentend can be formed, e.g., by coupling the plurality of optical fiber inwhich the core diameters are the same and the clad diameters aredifferent. This enables the light-emitting area to be further decreasedwhen the optical fibers are arrayed, and brightness can be furtherincreased. When the light source module is partially broken, it is easyto change light source modules, by forming the plurality of opticalfibers with the optical fibers connected detachably with the connector.

When the spatial light modulator is arranged obliquely and thesuper-fine exposure is performed with the contracting optical system orthe same magnification optical system, by using the high-bright fiberarray light source or the fiber bundle light source, the focal depth ofthe focus beam which has passed through the spatial light modulator canbe taken deeply because irradiation NA of the spatial light modulator isdecreased, the deep focal depth can be obtained, there is no fatteningof the beam on the surface of the resist and in the resist, and thepatterning of the high aspect ratio can be performed more finely. Whenthe oblique channel whose wall surface is slanted is formed, the smoothpatterning can be performed.

In the exposure process, for example, the laser beam is irradiated tothe spatial light modulator, in which many pixel portions whose lightmodulation state is changed according to each control signal arearranged on the substrate, and modulated with each pixel portion of thespatial light modulator.

A micro-mirror device (DMD; Digital Micro-mirror Device), in which manymicro-mirrors whose angle of the reflection plane is changeableaccording to each control signal are arranged two-dimensionally on thesubstrate (for example, silicon substrate), can used as the spatiallight modulator. The spatial light modulator may be include anone-dimensional grating light valve (GLV) in which many movable gratingswhich are provided with a ribbon-shaped reflection plane and movableaccording to the control signal and many fixed gratings which areprovided with the ribbon-shaped reflection plane are alternatelyarranged in parallel. A liquid crystal shutter, in which many liquidcrystal cells which can be shut the transmitted light according to eachcontrol signal are two-dimensionally arranged on the substrate, arraymay be used.

It is preferable that the micro-lens array including micro-lenses, whichare provided corresponding to each pixel portion of the spatial lightmodulator and condense the laser beam in each pixel, is arranged on theoutgoing side of the spatial light modulator. When the micro-lens arrayis arranged, since the laser beam modulated with each pixel portion ofthe spatial light modulator is condensed according to each pixel witheach micro-lens in the micro-lens array, even if the exposure area inthe exposed surface is enlarged, the size of each beam spot can becontracted and the fine exposure can be performed.

In order to achieve the above-described eighth and ninth objects of theinvention, there is provided a bleaching apparatus, wherein thebleaching apparatus comprising chemical solution impregnating means forimpregnating fiber prior to dyeing with a chemical solution containing aoxidizing agent or a reducing agent, and laser irradiating means whichincludes an incorporated laser light source including a plurality oflaser diodes, one optical fiber, and a condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam to an incident end of the opticalfiber, and pulse-irradiates cloth impregnated with the chemical solutionwith the laser beam whose wavelength ranges from 200 nm to 450 nm.

In the bleaching apparatus of the invention, the fiber prior to thedyeing is impregnated with the chemical solution containing theoxidizing agent or the reducing agent by the chemical solutionimpregnating means. The cloth impregnated with the chemical solution ispulse-irradiated with the laser beam whose wavelength ranges from 200 nmto 450 nm from the laser irradiating means.

The incorporated laser light source includes the plurality of laserdiodes, one optical fiber, and the condensing optical system whichcondenses the laser beam emitted from each of the plurality of laserdiodes and couples the condensed beam to an incident end of the opticalfiber. Since the plurality of laser beams are incorporated by utilizingthe optical fiber in the incorporated laser light source, theincorporated laser light source is the high output and the highbrightness. Since the laser irradiating means includes the incorporatedlaser light source having the high output and high brightness, highenergy density necessary for the bleaching can be easily obtained in thebleaching apparatus of the invention. Since the incorporated laser lightsource is formed with the laser diode which provides continuousoperation and excellent output stability, the short-pulsed laser beamcan be irradiated, energy efficiency is high, the bleaching can beperformed at high speed, and maintenance is easy and the bleachingapparatus is low-cost, compared with an apparatus using an excimerlaser.

In the bleaching apparatus, from the viewpoint of promoting thebleaching and increasing the processing, it is preferable that thewavelength of the laser beam irradiated from the laser irradiating meansranges from 350 nm to 450 nm. In particular, it is preferable that thewavelength ranges from 400 nm to 415 nm, which is easy to increase theoutput in the GaN laser diode. From the viewpoint of reduction of damageof the fiber and increase of bleaching performance, it is preferablethat the wavelength ranges from 200 nm to 350 nm. Furthermore,considering that cost-reduction of the apparatus is achieved andhigh-speed processing is performed without using the optical system fora special material, the wavelength is preferably more than 400 nm.

Since the GaN laser diode is covalent bond, mobility of dislocation isextremely small compared with a GaAs system or an AlGaInP system, andthermal conductivity is much larger than that of the GaAs system or theAlGaInP system, so that the GaN laser diode has high COD (CatastrophicOptical Damage) level. Consequently, when the GaN laser diode ispulse-driven, the high output can be achieved. As a result, the outputcan be obtained as high as several hundreds mW to several tens W at apeak power by the shortening the pulse. Consequently, duty can bedecreased as small as about 0.1% to about 10%, so that the high energydensity can be obtained and the heat damage to the fiber can bedecreased.

The incorporated laser light source may include the laser diodes havingthe plurality of light-emitting points, one optical fiber, and thecondensing optical system which condenses the laser beam emitted fromeach of the plurality of light-emitting points of the laser diodeshaving the plurality of light-emitting points and couples the condensedbeam to an incident end of the optical fiber. For example, themulti-cavity laser can be used as the laser diode having the pluralityof light-emitting points.

For the incorporated laser light source, it is preferable to use theoptical fiber, in which the core diameter is uniform and the claddiameter of the outgoing end is smaller that that of the incident end.The high brightness of the light source can be achieved by decreasingthe clad diameter of the outgoing end. Considering that the diameter ofthe light-emitting point is decreased, it is preferable that the claddiameter of the outgoing end of the optical fiber is less than 125 μm,in view of the smaller diameter of the light-emitting point, it is morepreferable that the clad diameter of the outgoing end is not more than80 μm, and it is particularly preferable that the clad diameter of theoutgoing end is not more than 60 μm. The optical fiber in which the corediameter is uniform and the clad diameter of the outgoing end is smallerthat that of the incident end can be formed, e.g., by coupling theplurality of optical fiber in which the core diameters are the same andthe clad diameters are different. This enables the light-emitting areato be further decreased when the optical fibers are arrayed, and thebrightness can be further increased. When the light source module ispartially broken, it is easy to change light source modules, by formingthe plurality of optical fibers with the optical fibers connecteddetachably with the connector.

The laser irradiating means may include the plurality of incorporatedlaser light sources. For example, the laser irradiating means mayinclude the fiber array light source in which the plurality oflight-emitting points (outgoing end of the optical fiber) of theincorporated laser light source are arranged in the shape of the array,or the fiber array light source in which the light-emitting points ofthe incorporated laser light source are formed in the shape of thebundle. In the fiber any light source or the fiber array light source,since the plurality of optical fibers is bundled to form the lightsource, the further high output can be achieved. Consequently, thehigh-bright light source can be obtained at low cost, the focusing beamhaving the deep focal depth and high brightness can be obtained, and thelaser bleaching can be performed at high speed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an appearance of an exposureapparatus according to a first embodiment.

FIG. 2 is a perspective view showing a construction of a scanner in theexposure apparatus according to the first embodiment.

FIG. 3A is a plan view showing an area formed in the photosensitivematerial where exposure has been performed, and FIG. 3B shows anarrangement of an exposure area which is exposed with each exposurehead.

FIG. 4 is a perspective view showing a schematic construction of theexposure head in the exposure apparatus according to the firstembodiment.

FIG. 5A is a sectional view in a sub-scanning direction along an opticalaxis, which shows the construction of the exposure head shown in FIG. 4,and FIG. 5B is a side view showing the construction of the exposure headshown in FIG. 4.

FIG. 6 is a partially enlarged view showing the construction of adigital micro-mirror device (DMD).

FIGS. 7A and 7B are explanatory views showing for illustrating operationof DMD.

FIG. 8A is a plan view showing an arrangement and a scanning line ofexposure beam when DMD is not obliquely arranged, and FIG. 8B is a planview showing the arrangement and the scanning line of the exposure beamwhen DMD is obliquely arranged.

FIG. 9A is a perspective view showing the construction of a fiber arraylight source, FIG. 9B is a partially enlarged view of the fiber arraylight source shown in FIG. 9A, FIG. 9C is a plan view showing an arrayof emitting points at a laser outgoing portion, and FIG. 9D is a planview showing another array of the emitting points at the laser outgoingportion.

FIG. 10 shows the construction of a multimode type of optical fiber.

FIG. 11 is a plan view showing the construction of an incorporated laserlight source.

FIG. 12 is a plan view showing the construction of a laser module.

FIG. 13 is a side view showing the construction of the laser moduleshown in FIG. 12.

FIG. 14 is a partially side view showing the construction of the lasermodule shown in FIG. 12.

FIG. 15A is a sectional view along the optical axis, which shows a focaldepth in the exposure apparatus of the related art, and FIG. 15B is asectional view along the optical axis, which shows the focal depth inthe exposure apparatus according to the first embodiment.

FIG. 16A shows an example of a usage area of DMD, and FIG. 16B showsanother example of the usage area of DMD.

FIG. 17A is a side view when the usage area of DMD is appropriate, andFIG. 17B is a sectional view in the sub-scanning direction along theoptical axis of FIG. 17A.

FIG. 18 is a plan view showing for illustrating an exposure method inwhich a photosensitive material is exposed in single scanning of thescanner.

FIGS. 19A and 19B are plan views for illustrating the exposure method inwhich the photosensitive material is exposed in multiple scanning of thescanner.

FIG. 20 is a perspective view showing the construction of a laser array.

FIG. 21A is a perspective view showing the construction of amulti-cavity laser, and FIG. 21B is a perspective view of a multi-cavitylaser array in which the multi-cavity lasers shown in FIG. 21A arearranged in the shape of an array.

FIG. 22 is a plan view showing another construction of the incorporatedlaser light source.

FIG. 23 is a plan view showing another construction of the incorporatedlaser light source.

FIG. 24A is a plan view showing another construction of the incorporatedlaser light source, and FIG. 24B is a sectional view along the opticalaxis of FIG. 24A.

FIGS. 25A, 25B and 25C are explanatory views concerning concepts ofcorrection performed with an optical system of light intensitydistribution correction.

FIG. 26 is a graph showing a light intensity distribution when the lightsource has a Gaussian distribution and the light intensity distributionis not corrected.

FIG. 27 is a graph showing the light intensity distribution after thecorrection performed with the optical system of light intensitydistribution correction.

FIG. 28A is a sectional view along the optical axis, which shows theconstruction of another exposure head having a different focusingoptical system, FIG. 28B is a plan view showing a light figure projectedon an exposed surface when a micro-lens array or the like is not used,and FIG. 28C a plan view showing the light figure projected on anexposed surface when a micro-lens array or the like is used.

FIG. 29 is a perspective view showing another construction of the fiberarray light source.

FIG. 30 is a perspective view showing the construction of a rapidprototyping apparatus adopting a laser scanning method of the relatedart.

FIG. 31 is a perspective view showing the construction of the rapidprototyping apparatus adopting a movable mirror method of the relatedart.

FIG. 32 is a perspective view showing the appearance of the rapidprototyping apparatus according to a second embodiment.

FIG. 33 is a perspective view showing the construction of the scanner inthe rapid prototyping apparatus according to the second embodiment.

FIG. 34A is a plan view showing an example of an exposure pattern in anexposure region, FIG. 34B is a perspective view showing a state after afirst group of elements in FIG. 34A is exposed, and FIG. 34C is aperspective view showing the state after a second group of elements inFIG. 34A is exposed.

FIG. 35 is a perspective view showing the appearance of a stacking rapidprototyping apparatus according to a third embodiment.

FIG. 36 is a perspective view showing the construction of the scanner inthe stacking rapid prototyping apparatus according to the thirdembodiment.

FIG. 37 is a perspective view showing the construction of a microchipfor synthetic reaction.

FIGS. 38A to 38G are sectional views showing sequentially amanufacturing process of the microchip for synthetic reaction shown inFIG. 37

FIGS. 39A to 39C are sectional views showing an example of a thickeningfilm of a resist film.

FIGS. 40A and 40B are explanatory views for illustrating that etchingaccuracy is improved with thickening resist film.

FIG. 41 is a sectional view showing the resist film patterned in theshape of a taper.

FIG. 42 is a schematic construction of a bleaching apparatus accordingto a fifth embodiment.

FIG. 43 is a perspective view showing the construction of a laserirradiating portion in the bleaching apparatus.

FIG. 44A is a sectional view in a fiber array direction along theoptical axis, which shows the construction of an irradiating head, andFIG. 44B is a sectional view in the sub-scanning direction, which showsthe construction of the irradiating head.

FIG. 45A is a sectional view in the fiber array direction along theoptical axis, which shows another construction of an irradiating head,and FIG. 45B is a sectional view in the sub-scanning direction, whichshows the construction of the irradiating head.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Preferred embodiments of the invention will be described in detail belowreferring to the drawings.

[First Embodiment]

A first embodiment is the exposure apparatus including the exposure headexposing the photosensitive material with the light beam modulated bythe spatial light modulator according to the image data.

(Construction of the Exposure Apparatus)

As shown in FIG. 1, the exposure apparatus according to the embodimentof the invention includes a flat plate-shaped stage 152 which absorbs asheet-shaped photosensitive material 150 to a surface of the stage 152and maintains the photosensitive material 150. Two guides 158 extendingalong a stage-moving direction are placed on an upper surface of a thickplate-shaped setting table 156 which is supported by four legs 154.While the stage 152 is arranged so that a longitudinal direction of thestage 152 faces the stage-moving direction, the stage 152 is supportedby the guides 158 so as to be able to reciprocate. The exposureapparatus is provided with a driving device, which is not shown, fordriving the stage 152 along the guides 158.

A U-shaped gate 160 is provided in a central portion of the settingtable 156 so as to straddle a moving route of the stage 152. Each of endportions of the U-shaped gate 160 is fixed to both side faces of thesetting table 156. A scanner 162 is provided on one side across the gate160, plural detecting sensors 164 (for example, two sensors) whichdetect a leading end and a rear end of the photosensitive material 150are provided on the other side. The gate 160 is equipped with thescanner 162 and the detecting sensors 164, the scanner 162 and thedetecting sensors 164 is arranged above the stage-moving direction ofthe stage 152. The scanner 162 and the detecting sensors 164 areconnected to a controller, which is not shown, for controlling them.

As shown in FIGS. 2 and 3B, the scanner 162 includes plural exposureheads 166 (for example, fourteen heads) which are arrayed in asubstantially m-row and n-column matrix (for example, three rows andfive columns). In this example, four exposure head 166 are arranged inthe third row according to a width of the photosensitive material 150.When the specific exposure head arranged in the mth row and the nthcolumn is shown, it is indicated as “exposure head 166 _(mn)”.

An exposure area 168 exposed by the exposure head 166 is a rectangleshape having a short side in the sub-scanning direction. Accordingly,with moving stage 152, a band-shaped exposed region 170 is formed witheach exposure head 166 in the photosensitive material 150. When theexposure area exposed with the exposure head arranged in the mth row andthe nth column is shown, it is indicated as “exposure area 168 _(mn)”.

As shown in FIGS. 3A and 3B, each of exposure heads in each row, whichis arranged in the shape of a line, is arranged with a predeterminedinterval (natural number times of a long side of the exposure area,twice in the embodiment) in an array direction so that the band-shapedexposed region 170 is arranged in a direction crossed with thesub-scanning direction without a gap. Therefore, a portion between theexposure area 168 ₁₁ and the exposure area 168 ₁₂, where can not beexposed, can be exposed by the exposure area 168 ₂₁ and the exposurearea 168 ₃₁.

As shown in FIGS. 4, 5A, and 5B, each of the expose heads 166 ₁₁ to 166_(mn) includes a digital micro-mirror device (DMD) 50 as the spatiallight modulator which modulates the incident light beam in each pixelaccording to the image data. DMD 50 is connected to the controller whichis provided with a data processing portion and a mirror-driving controlportion and not shown. In the data processing portion of the controller,a control signal which drives and controls each micro-mirror in theregion of DMD 50, which should be controlled, is generated in eachexposure head 166 on the basis of the inputted image data. The regionwhich should be controlled is described later. In the mirror-drivingcontrol portion, an angle of a refection plane of each micro-mirror ofDMD 50 is controlled in each exposure head 166 on the basis of thecontrol signal generated with the image data processing portion. Thecontrol of the angle of the reflection plane is described later.

On a light incident side of DMD 50, a fiber array light source 66including a laser outgoing portion in which an outgoing end portions ofthe optical fibers (light-emitting point) are arranged in line along thedirection corresponding to the long side direction of the exposure area168, a lens system 67 which corrects the laser beam emitted from thefiber array light source 66 to condense the laser beam on DMD 50, amirror 69 which reflects the laser beam transmitted by the lens system67 to DMD 50 are arranged in order.

The lens system 67 includes a pair of combination lenses 71 whichparallels the laser beam emitted from the fiber array light source 66, apair of combination lenses 73 which corrects the paralleled laser beamso that the light intensity distribution of the paralleled laser beam isuniformed, condenser lens 75 which condenses the laser beam in which thelight intensity distribution is corrected an DMD. The combination lenses73 have function of widening the light flux in the portion close to theoptical axis of the lens and compressing the light flux in the portionfar away from the optical axis for the array direction of the laseroutgoing end, and also have the function of just passing the light forthe direction crossed at right angles with the array direction. TheCombination lenses 73 correct the laser light so that the lightintensity distribution is formed to be uniform.

Lens systems 54 and 58 which focus the laser beam reflected by DMD 50 ona scanning surface (exposed surface) 56 of the photosensitive material150 are arranged on a light reflecting side of DMD 50. The lens systems54 and 58 are arranged so that DMD 50 and the exposed surface 56 becomea conjugate relation.

As shown in FIG. 6, DMD 50 is one in which micro mirrors (micro-mirrors)62 are arranged on SRAM (memory cell) 60 while the mirror is supportedby a support rod, and DMD is a mirror device in which plural (forexample, 600 by 800 pieces) micro mirrors constituting the pixel arearranged in the shape of a grating. The micro-mirror 62 supported by thesupport rod is provided on the uppermost portion in each pixel, amaterial having high reflectivity such as aluminum is evaporated on thesurface of the micro-mirror 62. The reflectivity of the micro-mirror 62is not lower than 90%. Silicon gate CMOS-SRAM cell 60, which ismanufactured in a normal manufacturing line of a semiconductor memory,is arranged through the support rod including a hinge and a yokeimmediately below the micro-mirror 62, and DMD 50 is formed to bemonolithic (integral) as a whole.

When a digital signal is written in SRAM cell 60 of DMD 50, themicro-mirror 62 supported by the support rod is slanted within the rangeof ±α degrees (for example, ±10 degrees) from a diagonal as a centerrelative to a substrate side on which DMD 50 is arranged. FIG. 7A showsthe +α degree-slanted state of the micro-mirror 62 which is an on-state,and FIG. 7B shows the −α degree-slanted state of the micro-mirror 62which is an off-state. Accordingly, the incident light to DMD 50 isreflected toward the oblique direction of each micro-mirror 62 in such amanner that the slope of the micro-mirror 62 in each pixel of DMD 50 iscontrolled according to the image signal, as shown in FIG. 6.

FIG. 6 shows partially enlarged view of DMD 50 and an example in whichthe micro-mirror 62 is controlled by +α degrees or −α degrees. On-offcontrol of each micro-mirror 62 is performed with the controller whichis connected to DMD 50 and not shown. A light absorber (not shown) isarranged in the direction in which the light beam is reflected with theoff-state micro-mirror 62.

It is preferable that DMD 50 is arranged slightly obliquely so that theshort side of DMD 50 makes a given angle θ (for example, 1° to 5°) withsub-scanning direction. FIG. 8A shows a scanning trajectory of reflectedlight (exposure beam) 53 reflected with each micro-mirror when DMD 50 isnot slanted, FIG. 8B shows the scanning trajectory of the exposure beam53 when DMD 50 is slanted.

Plural sets of the micro-mirror column (for example, 600 sets) in whichplural micro-mirrors (for example, 800 pieces) are arranged in the longside direction are arranged in the short direction in DMD 50. As shownin FIG. 8B, by slanting DMD 50, a pitch P₂ of the scanning trajectory ofthe exposure beam 53, which is formed by each micro-mirror, becomesnarrower than a pitch p₁ of the scanning line in the case at DMD 50 isnot slanted, so that the resolution is remarkably improved. On the otherhand, since the slanted angle of DMD 50 is micro, a scanning width W₂ inthe case that DMD 50 is slanted and a scanning width W₁ in the case thatDMD 50 is not slanted are substantially the same.

The same scanning line is exposed in multiple (multiple exposures) withdifferent micro-mirror columns. Thus, micro quantity of an exposureposition can be controlled and the fine exposure can be realized by themultiple exposures. A joint portion between plural exposure headsarrayed in the main scanning direction can be connected without a stepby the micro quantity of the exposure position control.

The same effect can be obtained in such a manner that each micro-mirroris staggered while the micro-mirror is shifted by a given interval inthe direction crossed at right angles with the sub-scanning directioninstead of the slanted DMD 50.

As shown in FIG. 9A, the fiber array light source 66 includes plural(for example, 6 pieces) laser modules 64, one end of a multimode opticalfiber 30 is coupled to each laser module 64. The other end of themultimode optical fiber 30 is coupled to an optical fiber 31 in which acore diameter is the same as that of the multimode optical fiber 30 anda clad diameter is smaller than that of the multimode optical fiber 30,as shown in FIG. 9C, a laser outgoing portions 68 is formed in such amanner that the outgoing end portions (light-emitting point) of opticalfibers 31 are arranged in one line along the main scanning directioncrossed at right angles with the sub-scanning direction. As shown inFIG. 9D, the light-emitting points may be arranged in two lines alongthe main scanning direction.

As shown in FIG. 9B, the outgoing end portions of the optical fibers 31are fixed while the outgoing end portions are sandwiched between twosupport plates 65 having a flat surface. A transparent protecting plate63 such as glass is placed on the light outgoing side of the opticalfiber 31 in order to protect the end face of the optical fiber 31. Theprotecting plate 63 may be placed bringing the protecting plate 63 closeto the end face of the optical fiber 31, and placed so as to seal theend face of the optical fiber 31. However, light density is high, dustis easy to gather, and degradation easily occurs in the outgoing endportions of the optical fibers 31, the dust can be prevented fromadhering to the end face and the degradation can be delayed by placingthe protecting plate 63.

In this example, since the outgoing end portions of the optical fibers31 having the smaller clad diameter are arranged in one line without thegap, the multimode optical fiber 30 is stacked between the two adjacentmultimode optical fibers 30 in the larger clad diameter portion, theoutgoing end portions of the optical fibers 31 coupled to the stackedmultimode optical fibers 30 are arranged so as to be sandwiched betweenthe two outgoing end portions of the optical fibers 31 coupled to thetwo adjacent multimode optical fibers 30 in the larger clad diameterportion.

For example, as shown in FIG. 10, such optical fiber can be obtained byconnecting coaxially the optical fiber 31 having the smaller claddiameter ranging from 1 to 30 cm to the leading end portion on the laserbeam outgoing side of the multimode optical fiber 30, which has thelarger clad diameter. In the two optical fibers, the incident endportion of the optical fiber 31 is melted and coupled to the outgoingend portion of the multimode optical fiber 30 so that central axes ofboth optical fibers are coincided. As described above, the diameter of acore 31 a of the optical fiber 31 is the same as that of a core 30 a ofthe multimode optical fiber 30.

A shorter optical fiber in which the optical fiber having the smallerclad diameter is fused to the optical fiber having the small length andthe larger clad diameter may be coupled the outgoing end portion of themultimode optical fiber 30 through a ferule, an optical connector, orthe like. By coupling detachably the optical fiber to the outgoing endportion of the multimode optical fiber 30 with the optical connector orthe like, the leading end portion is easily changed when the opticalfiber having the smaller clad diameter is broken, and maintenance costfor the exposure head can be reduced. Hereinafter, sometimes the opticalfiber 31 is referred to as outgoing end portion of the multimode opticalfiber 30.

Any of a step index type of optical fiber, a grated index type ofoptical fiber, and a multi-type of optical fiber can be used as themultimode optical fiber 30 and the optical fiber 31. For example, thestep index type of optical fiber made by MITUBISHI CABLE INDUSTRIES,LTD. can be used. In the embodiment, the multimode opt fiber 30 and theoptical fiber 31 are the step index type of optical fiber. In themultimode of fiber 30, the clad diameter is 125 μm, the core diameter is25 μm, NA is 0.2, and transmittance of the incident end face coating isnot lower 99.5%. In the optical fiber 31, the clad diameter is 60 μm,the core diameter is 25 μm, and NA is 0.2.

Generally, in the laser beam of an infrared region, propagation loss isincreased as the clad diameter of the optical fiber is decreased.Therefore, the preferable clad diameter is determined according to awave range of the laser beam. However, the propagation loss is decreasedwith decreasing wavelength, in the laser beam having the wavelength of405 nm which is emitted from GaN laser diode, even if a thickness of theclad ((clad diameter−core diameter)/2) is decreased to about a half ofthe case that the infrared light having the wave range of 800 nm ispropagated and the thickness of the clad is decreased to about a quarterof the case that the infrared light for communication having the waverange of 1.5 μm is propagated, the propagation loss is not substantiallyincreased. Accordingly, the clad diameter can be reduced as small as 60μm. The laser beam having the high brightness and high light density canbe easily obtained by using the GaN laser diode.

However, the clad diameter of the optical fiber 31 is not limited to 60μm. Though the clad diameter of the optical fiber used for the fiberlight source of the related art is 125 μm, since the focal depth isdeepened as the clad diameter is decreased, the clad diameter of themultimode optical fiber is preferably not more than 80 μm, morepreferably not more than 60 μm, further more preferably not more than 40μm. On the other hand, since it is necessary that the core diameter isat least 3 to 4 μm, the clad diameter of the optical fiber 31 ispreferably not more than 10 μm.

The laser module 64 includes an incorporated laser light source (fiberlight source) shown in FIG. 11. The incorporated laser light sourceincludes plural (for example, 7 pieces) chip-shaped transverse multimodetype or singe mode type of GaN laser diodes LD1, LD2, LD3, LD4, LD5,LD6, and LD7 which are arranged and fixed on a heat block 10, collimatorlenses 11, 12, 13, 14, 15, 16, and 17 which are provided correspondingto each of the GaN laser diodes LD1 to LD7, a condenser lens 20, and theone multimode optical fiber 30. The number of the laser diodes is notlimited to 7. For example, 20 laser diode beams can be incident to themultimode optical fiber in which the clad diameter is 60 μm, the corediameter is 50 μm, and NA is 0.2, so that the necessary light intensityof the exposure head can be realized and the number of optical fiberscan be reduced.

All oscillation wavelengths of the GaN laser diodes LD1 to LD7 arecommon (for example, 405 nm), and all maximum outputs are also common(for example, 100 mW in the multimode laser and 30 mW in the singe modelaser). A laser having the wave range of 350 to 450 nm and theoscillation wavelength except 405 nm may be used as the GaN laser diodesLD1 to LD7.

As described in FIGS. 12 and 13, the above-described incorporated laserlight source and other optical elements are stored in a box-shapedpackage 40 whose upper portion is opened. The package 40 includes apackage cover 41 so as to be formed to close the opening, theincorporated laser light source is hermetically sealed in the closedspace (sealed space) formed with the package 40 and the package cover 41in such a manner that sealing gas introduced after degassing and theopening of the package 40 is closed with the package cover 41.

A base plate 42 is fixed to a bottom surface of the package 40, and anupper surface of the base plate 42 is equipped with the above-describedheat block 10, a condenser lens holder 45 which holds the condenser lens20, and a fiber holder 46 which holds the incident end portion of themultimode optical fiber 30. The outgoing end portions of the multimodeoptical fiber 30 are drawn from an aperture formed in a wall of thepackage 40 outward the package.

A side face of the heat block 10 is equipped with a collimator lensholder 44, the collimator lenses 11 to 17 are held with the collimatorlens holder 44. An aperture is formed in a side wall of the package 40,a leads 47 which supply driving current to the GaN laser diodes LD1 toLD7 is drawn through the aperture to the outside of the package.

In FIG. 13, in order to avoid complication of the figure, only the GaNlaser diode LD7 is indicated by the number in the plural GaN laserdiodes and only the collimator lens 17 is indicated by the number in theplural collimator lenses.

FIG. 14 shows a front shape of a mounting portion of the collimatorlenses 11 to 17. Each of the collimator lenses 11 to 17 is formed in thelong and thin shape in which a region including the optical axis of acircular lens having an aspheric surface is cut by a parallel plane. Thelong and thin-shaped collimator lens can be formed, e.g., by moldingresin or optical glass. In the collimator lenses 11 to 17, thecollimator lenses 11 to 17 are closely arranged in the array directionof the light emitting-point so that the length direction is crossed atright angles with the array direction (a lateral direction in FIG. 14)of the light-emitting point of the GaN laser diodes LD1 to LD7.

On the other hand, the laser, in which a light-emitting width has anactive layer of 2 μm and each of laser beams B1 to B7 are emitted in thestate in which spreading angles of the parallel and perpendiculardirections to the active layer are 10° and 30° respectively, is used asthe GaN laser diodes LD1 to LD7. The GaN laser diodes LD1 to LD7 arearrayed so that the light emitting points are arranged in one line inthe direction parallel to the active layer.

Accordingly, the laser beams B1 to B7 emitted from each light-emittingpoint is incident to the collimator lenses 11 to 17 in the state inwhich the direction of the larger spreading angle corresponds to thelengthwise direction and the direction of the smaller spreading anglecorresponds to the width direction (direction crossed at right angleswith the lengthwise direction). That is to say, the width of eachcollimator lenses 11 to 17 is 1.1 mm and the length of each collimatorlenses 11 to 17 is 4.6 mm, beam diameters in horizontal and verticaldirections of the laser beams B1 to B7 incident to the collimator lenses11 to 17 are 0.9 mm and 2.6 mm respectively. In each of collimatorlenses 11 to 17, a focal length f₁ is 3 mm, NA is 0.6, and a lensarranging pitch is 1.25 mm.

The condenser lens 20 is formed in the long and thin shape in which aregion including the optical axis of a circular lens having an asphericsurface is cut by a parallel plane. The condenser lens 20 is long in thearray direction of the collimator lenses 11 to 17, i.e., the horizontaldirection, and short in the direction perpendicular to the arraydirection. In condenser lens 20, a focal length f₂ is 23 mm and NA is0.2. The condenser lens 20 is also formed, e.g., by molding the resinand the optical glass.

(Oeration of the Exposure Apparatus)

Operation of the above-described exposure apparatus will be describedbelow.

In each exposure head 166 of the scanner 162, each of the laser beamsB1, B2, B3, B4, B5, B6, and B7 emitted from each of the GaN laser diodesL1 to L7 constituting the incorporated laser light source of the fiberarray light source 66 with a divergent state is paralleled with thecorresponding collimator lenses 11 to 17. The paralleled laser beams B1to B7 are condensed with the condenser lens 20 and converged on theincident end face of the core 30 a of the multimode optical fiber 30.

In the embodiment, a beam-condensing optical system is formed with thecollimator lenses 11 to 17 and the condenser lens 20, an incorporatedoptical system is formed with the beam-condensing optical system and themultimode optical fiber 30. That is to say, the laser beams B1 to B7condensed with the condenser lens 20 are incident to the core 30 a ofthe multimode optical fiber 30 to be propagated into the optical fiber,and incorporated into one laser beam B to be emitted from the opticalfiber 31 coupled to the outgoing end portion of the multimode opticalfiber 30.

In each laser module, coupling efficiency of the laser beams B1 to B7 tothe multimode optical fiber 30 is 0.85, when each output of the GaNlaser diodes L1 to L7 is 30 mW, the incorporated laser beam B having theoutput of 180 mW (=30 mW×0.85×7) can be obtained for each optical fiber31 arranged in the shape of the array. Accordingly, the output is about1 W (=180 mW×6) at the laser outgoing portion 68 where the six opticalfibers 31 are arranged in the shape of the array.

The light-emitting points having high brightness are arranged in oneline along the main scanning direction at the laser outgoing portion 68of the fiber array light source 66. Since the fiber light source of therelated art, in which the laser beam from the single laser diode iscoupled to one optical fiber, is the low output, the desired output cannot be obtained unless many columns of the laser light source arearranged, however, since the incorporated laser light source used in theembodiment is the high output, the desired output can be obtained withfew columns of the laser light source, e.g., only one column of thelaser light source.

For example, in the fiber light source of the related art in which thelaser diode is coupled to the optical fiber with 1:1, normally the laserhaving the output of about 30 mW is used as the laser diode and themultimode optical fiber in which the core diameter is 50 μm, the claddiameter is 125 μm, and NA (numerical aperture) is 0.2 is used as theoptical fiber. When the output of about 1 W is obtained, it is necessaryto bundle the 48 multimode optical fibers and the area of thelight-emitting region is 0.62 mm² (0.675 mm×0.925 mm), so that thebrightness at the laser outgoing portion 68 is 1.6×10⁶ (W/m²) and thebrightness per one optical fiber is 3.2×10⁶ (W/m²).

On the other hand, as described above, the output of about 1 W can beobtained in the embodiment. Since the area of the light-emitting regionis 0.0081 mm² (0.325 mm×0.025 mm) at the laser outgoing portion 68, thebrightness at the laser outgoing portion 68 is 123×10⁶ (W/m²), so thatthe high brightness about 80 times the related art can be achieved.Since the brightness per one optical fiber is 90×10⁶ (W/m²), the highbrightness about 28 times the related art can be achieved.

Referring to FIGS. 15A and 15B, difference in the focal depth betweenthe exposure heads of the related art and the embodiment will bedescribed. The diameter in the sub-scanning direction of thelight-emitting region is 0.675 mm in a bundle-shaped fiber light sourcein the exposure head of the related art, and the diameter in thesub-scanning direction of the light-emitting region is 0.025 mm in thefiber array light source in the exposure head of the embodiment. Asshown in FIG. 15A, since the light-emitting region of a light source 1(bundle-shaped fiber light source) is large in the exposure head of therelated art, the angle of the light flux incident to DMD 3 becomeslarge, as a result, the angle of the light flux incident to a scanningsurface 5 becomes large. Consequently, the beam diameter is easy tofatten for the beam-condensing direction (shift in the focusingdirection).

On the other hand, as shown in FIG. 15B, since the diameter in thesub-scanning direction of the light-emitting region of the fiber arraylight source 66 is small in the exposure head of the embodiment, theangle of the light flux passing the lens system 67 and being incident toDMD 50 becomes small, as a result, the angle of the light flux incidentto the scanning surface 56 becomes large. That is to say, the focaldepth is deepened. In this embodiment, the diameter in the sub-scanningdirection of the light-emitting region is about 30 times the relatedart, the focal depth corresponding to almost a diffraction limit can beobtained. Accordingly, it is preferable for the exposure of a microspot. Effect on the focal depth is remarkable and effective as thenecessary light intensity of the exposure head is enlarged. In theembodiment, the size of one pixel projected onto the exposure surface is10 μm by 10 μm. Though DMD is a reflection type of spatial opticalmodulator, a development is used for explanation of optical relation inFIGS. 15A and 15B.

The image data according to an exposure pattern is inputted to thecontroller which is connected to DMD 50 and not shown, and temporarilystored in the frame memory in the controller. The image data is the datadensity of each pixel constituting the image is indicated by binaryvalue (presence or absence of recording of a dot).

The stage 152, in which the photosensitive material 150 is absorbed onthe surface, is moved at constant velocity from an upstream side of thegate 160 to a downstream side along the guide 158 with the drivingdevice which is not shown. When the stage 152 passes below the gate 160,the leading end of the photosensitive material 150 is detected with thedetecting sensor 164 attached to the gate 160, the plural lines of imagedata stored in the frame memory are sequentially read, and the controlsignal is generated in each exposure head 166 on the basis of the imagedata read with the data processing portion. Each of the micro-mirrors ofDMD 50 is on-off controlled in each exposure head 166 on the basis ofthe generated control signal with the mirror driving control portion.

When the laser beam is irradiated from the fiber array light source 66to DMD 50, the laser beam reflected in the case that the micro-mirror ofthe DMD 50 is on-state is focused on the exposed surface 56 of thephotosensitive material 150 with the lens systems 54 and 58. In suchway, the laser beam emitted from the fiber array light source 66 isturned on and off in each pixel and the photosensitive material 150 isexposed in the almost same pixel unit (exposure area 168) as the numberof using pixels of DMD 50. The photosensitive material 150 issub-scanned in the reverse direction of the stage moving direction withthe scanner 162 in such a manner that the photosensitive material 150 ismoved with the stage 152 at constant speed, and a band-shaped exposedregion 170 is formed in each exposure head 166.

As shown in FIGS. 16A and 16B, in the embodiment, 600 sets of themicro-mirror column, in which the 800 pieces of the micro-mirror arearranged in the main scanning direction, are arranged in thesub-scanning direction in DMD 50, however, the control is performed sothat only a part of the micro-mirror columns (for example, 800pieces×100 columns) are driven with the controller.

As shown in FIG. 16A, the micro-mirror column arranged in the centralportion of DMD 50 may be used, or, as shown in FIG. 16B, themicro-mirror column arranged in the end portion of DMD 50 may be used.When defect is generated in a part of the micro-mirrors, themicro-mirror column which is used may be appropriately changed accordingto conditions such that the micro-mirror column in which the defect isnot generated is used.

Since there are limitations of the data processing speed of DMD 50 anddecision of modulating speed per one line is proportional to the numberof the using pixels, the modulating speed per one line is increased byusing the part of the micro-mirror columns. On the other hand, it is notnecessary to use all the pixels in the sub-scanning direction in thecase of the exposure method in which the exposure head is continuouslymoved relative to the exposure surface.

When the 300 sets of the micro-mirror column in the 600 sets are used,the two times modulating speed can be achieved compared with the casethat in which all the 600 sets are used. When the 200 sets of themicro-mirror column in the 600 sets are used, the three times modulatingspeed can be achieved compared with the case that in which all the 600sets are used. That is to say, the region of 500 mm in the sub-scanningdirection can be exposed in 17 seconds. Furthermore, when only the 100sets of the micro-mirror column in the 600 sets are used, the six timesmodulating speed can be performed. That is to say, the region of 500 mmin the sub-scanning direction can be exposed in 9 seconds.

It is preferable that the number of using micro-mirror columns, i.e.,the number of micro-mirrors arranged in the sub-scanning direction isnot lower than 10 and not more than 200, more preferably not lower than10 and not more than 100. Because the area per one micro-mirrorcorresponding to one pixel is 15 μm by 15 μm, converting the area intothe occupying area of DMD 50, it is preferable that the area is notlower than 12 mm by 150 μm and not more than 12 mm by 3 mm, morepreferably not lower than 12 mm by 150 μm and not more than 12 mm by 1.5mm.

When the number of using micro-mirror column is within theabove-described range, as shown in FIGS. 17A and 17B, the laser beamemitted from the fiber array light source 66 can be substantiallyparalleled with the lens system 67 and irradiated to DMD 50. It ispreferable that the irradiating area where the laser beam is irradiatedwith DMD 50 corresponds to the using area of DMD 50. When theirradiating area is wider than the using area, usable efficiency of thelaser beam is decreased.

Though it is necessary that the diameter in the sub-scanning directionof the light beam condensed on DMD 50 is decreased according to thenumber of micro-mirror arranged in the sub-scanning direction with thelens system 67, when the number of using micro-mirrors is less than 10,it is not preferable because the angle of the light flux incident to DMD50 and the focal depth of the light beam shallows in the scanningsurface 56. When the number of using micro-mirrors is not more than 200,it is preferable in view of the modulating speed. However DMD 50 is thereflection type of spatial optical modulator, the development is usedfor explanation of the optical relation in FIGS. 17A and 17B.

When the sub scanning of the photosensitive material 150 with thescanner 162 is finished and the rear end of the photosensitive material150 is detected with the detecting sensor 164, the stage 152 is returnedto a home position located on the upstream side of the gate 160 alongthe guide 158 with the driving device which is not shown, and then movedagain from the upstream side to down stream side of the gate 160 alongthe guide 158 at constant speed.

As described above, though the exposure apparatus of the embodimentincludes DMD in which 600 sets of the micro-mirror column, in which the800 pieces of the micro-mirror are arranged in the main scanningdirection, are arranged in the sub-scanning direction, the control isperformed so that only a part of the micro-mirror columns are drivenwith the controller, the modulating speed per one line is increasedcompared with the case that all the micro-mirror columns are driven.Consequently, the exposure can be performed at high speed.

The fiber array light source having the high brightness, in which theoutgoing end portions of the optical fiber of the incorporated laserlight source are arranged in the shape of the array, is used as thelight source irradiating DMD, so that the exposure apparatus having thehigh output and the deep focal depth can be realized. Furthermore, thenumber of fiber bight sources necessary for obtaining the desired outputis decreased by enlarging the output of each fiber light source, so thatcost-reduction of the exposure apparatus can be achieved.

Particularly, in the embodiment, since the clad diameter of the outgoingend of the optical fiber is smaller than that of the incident end, thediameter of the light-emitting portion becomes smaller, so that the highbrightness of the fiber array light source is achieved. Consequently,the exposure apparatus having the deeper focal depth can be realized.For example, even in the case of the exposure of the super-fineresolution in which the beam diameter is not more than 1 μm and theresolution is not more 0.1 μm, the deep focal depth can be obtained andthe super-fine exposure can be performed at high speed. Accordingly, itis preferable to the exposure process for a thin film transistor (TFT)necessary for the high resolution.

Modification and the like of the above-described exposure apparatus willbe described below.

(Application of the Exposure Apparatus)

The above-described exposure apparatus can be preferably used forapplications such as the exposure of a dry film resist (DFR) in themanufacturing process of a printed wiring board (PWB), the formation ofa color filter in the manufacturing process of a liquid crystal device(LCD), the exposure of DFR in the manufacturing process of TFT, and theexposure of DFR in the manufacturing process of a plasma display panel(PDP).

Further, the exposure apparatus can be used for various kinds of lasermachining such as laser abrasion in which part of the material isremoved by evaporating and flying the material with the laserirradiation, sintering, and lithography. Since the exposure apparatus isthe high output and the exposure can be performed at the high speed andthe long focal depth, the exposure apparatus can be used formicromachining such as the laser abrasion. For example, the exposureapparatus can be used in order that the resist is removed according tothe pattern with the laser abrasion instead of the developmentprocessing and PWB is formed, or the pattern of PWB is directly formedwith the laser abrasion without using the resist. The exposure apparatuscan be also used for the formation of a micro channel having a channelwidth of several tens μm in a lob-on chip in which mixture, reaction,separation, detection, and the like of many solutions are integrated ona glass or plastic chip.

In the exposure apparatus, since the GaN laser diode is used as thefiber array light source, the exposure apparatus can be preferably usedfor the laser machining. That is to say, the short pulse operation canbe performed in the GaN laser diode, so that sufficient power for thelaser abrasion can be obtained. Unlike a solid state laser whoseoperating speed is slow, the high speed operation can be performed at arepeating frequency of about 10 MHz because of the laser diode, so thatthe high speed exposure can be performed. Further, metal has large lightabsorption factor of the laser beam near the wavelength of 400 nm, andit is easy to transform the laser beam into thermal energy, so that thelaser abrasion and the like can be performed at high speed.

When a liquid resist used for the patterning of TFT or the liquid resistused for the patterning of the color filter is exposed, in order toeliminate a decrease in sensitivity (desensitization) caused by oxygeninhibition, it is preferable to expose the material which is exposed ina nitrogen atmosphere. The oxygen inhibition of photo-inducedpolymerization reaction is suppressed by exposing the material in thenitrogen atmosphere, the sensitivity of the resist is increased, and thehigh speed exposure can be performed.

Both a photon mode photosensitive material in which information isdirectly recorded with the exposure and a heat mode photosensitivematerial in which the information is recorded with heat generated by theexposure are used for the exposure apparatus. When the photon modephotosensitive material is used, the GaN laser diode, a wavelengthconversion type of solid state laser, or the like is used as the laserdevice, when the heat mode photosensitive material is used, an AlGaAslaser diode (infrared laser) or the solid state laser is used as thelaser device.

(Other Spatial Light Modulator)

However, the case in which the micro-mirror of DMD is partially drivenwas described in the above-described embodiment, even if long and thinDMD, in which many micro-mirrors whose angle of the reflection plane ischangeable according to each control signal are two-dimensionallyarranged, is used on the substrate whose length of the directioncorresponding to a predetermined direction is longer that that of thedirection intersecting with the predetermined direction, the modulatingspeed can be also increased in the same way, because the number ofmicro-mirrors controlling the angle of the reflection plane is reduced.

Though the exposure head including DMD of the spatial light modulatorwas described in the above-described embodiment, for example, even inthe case that a MEMS (Micro Electro Mechanical Systems) type of spatiallight modulator (SLM), or the spatial light modulator except the MEMStype of spatial light modulator such as an optical device (PLZT device)modulating the transmitted light with electro-optic effect, and a liquidcrystal shutter (FLC) is used, the modulating speed per one pixel andper one main scanning line can be increased by using a part of the pixelportions for the entire pixel portions arranged on the substrate, sothat the same effect can be obtained.

A grating light valve (GLV) in which many movable gratings which isprovided with a ribbon-shaped reflection plane and movable according tothe control signal and many fixed gratings provided with theribbon-shaped reflection plane are alternately arranged in parallel, ora light valve array in which the GLV devices are arranged in the shapeof the array can be used as the MEMS type of spatial light modulator.

MEMS is a generic name of micro-system in which the sensor, actuator,and control circuit of a micro-size are integrated with themicromachining technology, the MEMS type of spatial light modulatormeans the spatial light modulator driven by the electro-mechanicaloperation utilizing electrostatic power.

(Other Exposure Method)

As shown in FIG. 18, similarly to the above-described embodiment, theentire surface of the photosensitive material 150 may be exposed in theone time scanning toward the X-direction with the scanner 162, as shownin FIGS. 19A and 19B, the entire surface of the photosensitive material150 may be exposed in the plural times scanning by repeating thescanning and the movement such that the scanner 162 is moved by one stepand the scanning toward the X-direction is performed after thephotosensitive material 150 is scanned toward the X-direction with thescanner 162. In the embodiment, the scanner includes 18 exposure heads166.

(Other Laser Devices (Light Sources))

Though the case in which the fiber array light source including theplural incorporated laser light source is used was described in theabove-described embodiment, the laser device is not limited to the fiberarray light source in which the incorporated laser light source isarrayed. For example, the fiber array light source in which the fiberlight source including one optical fiber emitting the laser beamincident from the single laser diode having one light-emitting point isarrayed can be used. However, it is more preferable that theincorporated laser light source which can take the deep focal depth isused.

For example, as shown in FIG. 20, the laser array in which plural (forexample, 7 laser diodes) chip-shaped laser diodes LD1 to LD7 arearranged on a heat block 100 can be used as the light source includingthe plural light-emitting points. Also, as shown in FIG. 21A, achip-shaped multi-cavity laser 110 in which plural (for example, 5points) light-emitting points 110 a are arranged in a predetermineddirection is known. Since the light-emitting points can be arranged withgood accuracy of position in the multi-cavity laser 110 compared withthe arrangement of the chip-shaped laser diode, it is easy toincorporate the laser beam emitted from each light-emitting point.However, it is easy to generate deformation in the multi-cavity laser110 during the manufacture of the laser when the number oflight-emitting points is increased, so that it is preferable that thenumber of light-emitting points 110 a is not more than 5.

In the exposure head of the invention, the multi-cavity laser 110 or, asshown in FIG. 21B, a multi-cavity laser array in which the pluralmulti-cavity lasers 110 are arranged on the heat block 100 in the samedirection as the array direction of the light-emitting points 110 a ofeach chip can be used as the laser device (light source).

The incorporated laser light source is not limited to one in which thelaser beam emitted from the plural chip-shaped laser diodes areincorporated. For example, as shown in FIG. 22, the incorporated laserlight source including the chip-shaped multi-cavity laser 110 having theplural (for example, 3 points) light-emitting points 110 a can be used.This incorporated laser light source includes the multi-cavity laser110, one multimode optical fiber 130, and a condenser lens 120. Themulti-cavity laser 110 can include, e.g., the GaN laser diode having theoscillating wavelength of 405 nm.

In the above-described construction, each of laser beams B emitted fromeach of plural light-emitting points 110 a of the multi-cavity laser 110is condensed with the condenser lens 120 and incident to a core 130 a ofthe multimode optical fiber 130. The laser beams incident to the core130 a are propagated in the optical fiber, and incorporated into onelaser beam to be emitted.

The coupling efficiency of the laser beam B to the multimode opticalfiber 130 can be increased in such a manner that a convex lens havingthe focal length substantially equal to the core diameter of themultimode optical fiber 130 or a rod lens collimating the outgoing beamfrom the multi-cavity laser 110 only in a plane perpendicular to itsactive layer is used as the condenser lens, while the plurallight-emitting points 110 a of the multi-cavity laser 110 are providedtogether within the width substantially equal to the core diameter ofthe multimode optical fiber 130.

As shown in FIG. 23, the multi-cavity laser 110 including the plural(for example, 3 points) light-emitting points can be used and theincorporated laser light source including a laser array 140 in which theplural (for example, 9 lasers) multi-cavity laser 110 are arranged atthe same interval on a heat block 111 can be used. The pluralmulti-cavity lasers 110 are arranged and fixed in the same direction asthe array direction of the light-emitting point 110 a of each chip.

The incorporated laser light source includes a laser array 140, plurallens arrays 114 arranged corresponding to each multi-cavity laser 110,one rod lens 113 arranged between the laser array 140 and the plurallens arrays 114, one multimode optical fiber 130, and the condenser lens120. The lens array 114 includes the plural micro-lenses correspondingto the light-emitting point of the multi-cavity laser 110.

In the above-described construction, each of the laser beams B emittedfrom each of the plural light-emitting points 110 a of the pluralmulti-cavity lasers 110 are condensed in a predetermined direction withthe rod lens 113, and then paralleled with each micro-lens of the lensarray 114. A paralleled laser beam L is condensed with the condenserlens 120 and incident to a core 130 a of the multimode optical fiber130. The laser beam which has been incident to the core 130 a ispropagated in the optical fiber and incorporated into one beam to beemitted.

Further, another embodiment of the incorporated laser light source willbe shown. As shown in FIGS. 24A and 24B, in the incorporated laser lightsource, a heat block 182 whose cross section in the optical axisdirection is L-shaped is mounted on a substantially rectangular heatblock 180 and a housing space is formed between two heat blocks. Theplural (for example, 2 lasers) multi-cavity lasers 110 in which theplural (for example, 5 points) light-emitting points are arranged in theshape of the array are fixed on the upper surface of the L-shaped heatblock 182 while the multi-cavity lasers 110 are arranged at the sameinterval in the same direction as the array direction of thelight-emitting point 110 a of each chip.

A concave portion is formed in the substantially rectangular heat block180, the plural (for example, 2 lasers) multi-cavity lasers 110 in whichthe plural (for example, 5 points) light-emitting points are arranged inthe shape of the array are arranged so that its light-emitting point isplaced on the same vertical plane as the light-emitting point arrangedon the upper surface of the heat block 182.

A collimator lens array 184 in which the collimator lenses are arrangedcorresponding to the light-emitting point 110 a of each chip on theoutgoing side of the laser beam of the multi-cavity laser 110. Thecollimator lens array 184 is arranged so that the lengthwise directionof each collimator lens corresponds to the direction of the largerspread angle (fast axis direction) of the laser beam and the widthdirection of each collimator lens corresponds to the direction of thesmaller spread angle (slow axis direction). Thus, by arraying andintegrating the collimator lens, the number of parts is decreased andcost-reduction can be achieved, while space utilization efficiency ofthe laser beam is improved and output of the incorporated laser lightsource is increased.

Further, one multimode optical fiber 130 and the condenser lens 120which condenses and couples the laser beam on the incident end of themultimode optical fiber 130 are arranged on the outgoing side of thelaser beam of the collimator lens array 130.

In the above-described construction, each of the laser beams B emittedfrom each of the plural light-emitting points 110 a of the pluralmulti-cavity lasers 110 are paralleled with the collimator lens array184, condensed with the condenser lens 120, and incident to the core 130a of the multimode optical fiber 130. The laser beam which has beenincident to the core 130 a is propagated in the optical fiber andincorporated into one beam to be emitted.

As described above, in the incorporated laser light source, particularlythe high output can be achieved with multi-step arrangement of themulti-cavity laser and the array of the collimator lenses. Since thebrighter fiber array light source or bundle fiber light source can beformed by using the incorporated laser light source, it is particularlypreferable for the fiber light source constituting the laser lightsource of the exposure apparatus of the invention.

The laser module in which each incorporated laser light source can bestored in a casing and the outgoing end portion of the multimode opticalfiber 130 is drawn from the casing can be formed.

Though the case in which the high brightness of the fiber array lightsource is achieved by coupling other optical fiber, in which the corediameter is the same as that of the multimode optical fiber and the claddiameter is smaller than that of the multimode optical fiber, to theoutgoing end of the multimode optical fiber of the incorporated laserlight source in the embodiment, for example, as shown in FIG. 29, themultimode optical fiber 30 having the clad diameter of 125 μm, 80 μm, 60μm, and the like may be used without coupling other optical fiber to theoutgoing end.

(Optical System for Correcting Light Intensity Distribution)

In the embodiment, an optical system for correcting light intensitydistribution including a pair of combination lenses is used in theexposure head. In the optical system for correcting light intensitydistribution, the light flux width is changed at each outgoing positionso that a ratio of the light flux width of a peripheral portion to thelight flux width of the central portion near the optical axis isdecreased on the outgoing side compared with the incident side, and thelight intensity distribution is corrected so as to be substantiallyuniformed at the irradiated surface when the parallel light flux isirradiated from the light source to DMD. The operation of the opticalsystem for correcting light intensity distribution will be describedbelow.

As shown in FIG. 25A, the case in which the total light flux widths H0and H1 of the incident light flux and outgoing light flux are the samewill be described at first. In FIG. 25A, portions indicated withreference numerals 51 and 52 virtually show the incident plane and theoutgoing plane in the optical system for correcting light intensitydistribution.

In the optical system for correcting light intensity distribution, it isassumed that a light flux width h0 of the light flux incident to thecentral portion near an optical axis Z1 and a light flux width h1 of thelight flux incident to the peripheral portion are the same (h0=h1). Theoptical system for correcting light intensity distribution provides theoperation such that the light flux width h0 is extended in the incidentlight flux of the central portion and the light flux width h1 iscontracted in the incident light flux of the peripheral portion for thelight having the same light flux widths h0 and h1 on the incident side.That is to say, the optical system for correcting light intensitydistribution acts on an outgoing light flux width of the central portionh10 and an outgoing light flux width of the peripheral portion h11 so asto become h11<h10. Indicating the ratio of the light flux width, theratio of the light flux width of the peripheral portion to the lightflux width of the central portion on the outgoing side “h11/h10” becomessmaller compared with the ratio (h1/h0=1) (h11/h10<1).

By changing the light flux width, the light flux in the central portion,in which normally the light intensity distribution is enlarged, can beutilized to the peripheral portion where the light intensity is lacked,and the light intensity distribution is substantially uniformed on theirradiated surface without reducing the light utilization efficiency asa whole. A degree of uniformity is set so that nonuniformity of thelight intensity is within 39% in the effective region, preferably within20%.

The operation and effect generated by the optical system for correctinglight intensity distribution is also the same in the case that the totallight flux width is changed on the incident side and the outgoing side(FIGS. 25B and 25C).

FIG. 25B shows the case in which the total light flux width H0 on theincident side is “contracted” to a width H2 and the light is emitted(H0>H2). Even in such case, the optical system for correcting lightintensity distribution provides the operation such that the light fluxwidth h10 of the central portion is increased compared with theperipheral portion or the light flux width h11 on the peripheral portionis decreased compared with the central portion on the outgoing side forthe light having the same light flux widths h0 and h1 on the incidentside. Considering a reduction ratio of the light flux, the opticalsystem for correcting light intensity distribution provides theoperation such that the reduction ratio for the incident light flux ofthe central portion is decreased compared with the peripheral portion,and the reduction ratio for the incident light flux of the peripheralportion is increased compared with the central portion. In this case,the ratio of the light flux width of the peripheral portion to the lightflux width of the central portion “H11/H10” becomes smaller comparedwith the ratio (h1/h0=1) on the incident side (h11/h10<1).

FIG. 25C shows the case in which the total light flux width H0 on theincident side is magnified to a width H3 and the light is emitted(H0<H3). Even in such case, the optical system for correcting lightintensity distribution provides the operation such that the light fluxwidth h10 of the central portion is increased compared with theperipheral portion or the light flux width h11 on the peripheral portionis decreased compared with the central portion on the outgoing side forthe light having the same light flux widths h0 and h1 on the incidentside.

Considering a magnification ratio of the light flux, the optical systemfor correcting light intensity distribution provides the operation suchthat the magnification ratio for the incident light flux of the centralportion is increased compared with the central portion, and themagnification ratio for the incident light flux of the peripheralportion is decreased compared with the central portion. In this case,the ratio of the light flux width of the peripheral portion to the lightflux width of the central portion “h11/h10” becomes smaller comparedwith the ratio (h1/h0=1) on the incident side (h11/h10<1).

As described above, in the optical system for correcting light intensitydistribution, the light flux width in each outgoing position is changed,and the ratio of the light flux width of the peripheral portion to thelight flux width of the central portion near the optical axis Z1 on theoutgoing side is formed to be smaller than that on the incident side, sothat, for the light having the same light flux width on the incidentside, the light flux width of the central portion is increased comparedwith the peripheral portion and the light flux width of the peripheralportion is decreased compared with the central portion on the outgoingside. Consequently, the light flux in the central portion can beutilized to the peripheral portion and the light flux cross section inwhich the light intensity distribution is substantially uniformed can beformed without reducing the light utilization efficiency as a whole.

An example of specific lens data of the pair of combination lenses usedas the optical system for correcting light intensity distribution isshown. In this embodiment, like the case in which the light source isthe laser array light source, the lens data of the case in which thelight intensity distribution at the cross section of the outgoing lightflux is the Gaussian distribution is shown. When one laser diode isconnected to the incident end of the single mode optical fiber, thelight intensity distribution of the outgoing light flux from the opticalfiber becomes the Gaussian distribution. The embodiment is applicable tosuch case. The embodiment is also applicable to the case in which thelight intensity of the central portion is larger than that of theperipheral portion in such a manner that the core diameter of themultimode optical fiber is decreased to close to the construction of thesingle mode optical fiber.

Table 1 shows basic lens data.

TABLE 1 BASIC LENS DATA Si Di (DISTANCE Ni (SURFACE Ri (CURVATUREBETWEEN (REFRACTIVE NUMBER) RADIUS) SURFACES) INDEX) 01 ASPHERIC 5.0001.52811 SURFACE 02 ∞ 50.000 03 ∞ 7.000 1.52811 04 ASPHERIC SURFACE

As can be seen from Table 1, the pair of combination lenses includes tworotationally-symmetric aspherical lenses. Assuming that the surface onthe light-incident side of a first lens which is placed on thelight-incident side is a first surface and the surface on thelight-outgoing side is a second surface, the first surface is theaspheric shape. Assuming that the surface on the light-incident side ofa second lens which is placed on the light-incident side is a thirdsurface and the surface on the light-outgoing side is a fourth surface,the fourth surface is the aspheric shape.

In Table 1, a surface number Si indicates the number of the ith (i=1 to4) surface, a curvature radius ri indicates the curvature of the ithsurface, and a distance between surfaces di indicates the distancebetween the ith surface and the i+1th surface an the optical axis. Aunit of a value of the distance between the surfaces di is millimeter.The refractive index Ni indicates the value of the refractive index forthe wavelength of 405 nm of an optical element including the ithsurface.

Table 2 shows aspheric surface data of the first and fourth surfaces.

TABLE 2 ASPHERIC SURFACE DATA FIRST FOURTH SURFACE SURFACE C −1.4098E−02−9.8506E−03   K −4.2192E+00 −3.6253E+01   a3 −1.0027E−04 −8.9980E−05  a4   3.0591E−05 2.3060E−05 a5 −4.5115E−07 −2.2860E−06   a6 −8.2819E−098.7661E−08 a7   4.1020E−12 4.4028E−10 a8   1.2231−13 1.3624E−12 a9  5.3753E−16 3.3965E−15  a10   1.6315E−18 7.4823E−18

The aspheric surface data indicates with a coefficient in the followingEquation A showing the aspherical shape.

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack & \; \\\left\lbrack {1} \right\rbrack & \; \\{Z = {\frac{C \cdot \rho^{2}}{1 + \sqrt{1 - {K \cdot \left( {C \cdot \rho} \right)^{2}}}} + {\sum\limits_{i = 3}^{10}{{ai} \cdot \rho^{i}}}}} & (A)\end{matrix}$

Each coefficient in Equation A is defined as follows.

-   Z: a length of a perpendicular dropped from a point on an aspheric    surface, which is located at a position of a height ρ from the    optical axis, to a tangent plane of an apex of the aspheric surface    (plane perpendicular to the optical axis) (mm)-   ρ: a distance from the optical axis (mm)-   K: constant of the cone-   C: a paraxial curvature (1/r, r: a paraxial curvature radius)-   ai: an aspherical coefficient of ith order

In numerical values shown in Table 2, a sign “E” indicates that thenumerical value following “E” is “power” having a base of 10, and thatthe numerical value shown by an exponential function whose base is 10 ismultiplied by the numerical value antecedent to “E”. For example, in thecase of “1.0E-02”, it shows “1.0×10⁻²”.

FIG. 27 shows the light intensity distribution of irradiating light,which is obtained with the pair of combination lenses shown in Table 1and Table 2. A horizontal axis shows a coordinate from the optical axis,and a vertical axis shows a light intensity ratio (light quantity ratio)(%). For comparison, FIG. 26 shows the light intensity distribution(Gaussian distribution) of irradiating light when the correction has notbeen performed. As can be seen from FIGS. 27 and 28, by performing thecorrection with the optical system for correcting light intensitydistribution, compared with the case in which the correction has notbeen performed, the substantial uniformity of the light intensitydistribution can be obtained. Consequently, the uniform exposure can beperformed with the uniform laser beam without reducing the lightutilization efficiency in the exposure head. The rod integrator, thefry-eye lens, or the like, which is usually used, may be used.

(Other Focusing Optical System)

In the above-described embodiment, though two pairs of combinationlenses is arranged as a focusing optical system on the light-reflectingside of DMD used for the exposure head, the focusing optical systemwhich enlarges and focuses the laser beam may be arranged. The exposurearea (image region) on the exposed surface can be magnified to thedesired size by magnifying the cross section of a light flux reflectedwith DMD.

For example, as shown in FIG. 28A, the exposure head can include DMD 50,a lighting device 144 which irradiates the laser bean to DMD 50, lenssystems 454 and 458 which magnify and focus the laser beam reflectedwith DMD 50, a micro-lens array 472 in which many micro-lenses 474 arearranged corresponding to each pixel of DMD 50, an aperture array 476 inwhich many aperture 478 are provided corresponding to each micro-lens ofthe micro-lens array 472, and lens systems 480 and 482 which focus thelaser beam passing through the aperture on the exposed surface 56.

In the exposure head, when the laser beam is irradiated from thelighting device 144, the cross section of the light flux line reflectedin the on-direction with DMD 50 is magnified to several times (forexample, double) with the lens systems 454 and 458. The magnified laserbeam is condensed with each micro-lens of the micro-lens array 472corresponding to each pixel of DMD 50, and passes the correspondingaperture of the aperture array 476. The laser beam which has passed theaperture is focused on the exposed surface 56 with the lens systems 480and 482.

In the focusing optical system, since the laser beam reflected with DMD50 is magnified to several times with the magnifying lens systems 454and 458 and projected onto the exposed surface 56, the total imageregion is increased. At this point, unless the micro-lens array 472 andthe aperture array 476 are arranged, as shown in FIG. 28B, one pixelsize (spot size) of each beam spot BS projected to the exposed surface56 becomes large according to the size of an exposure area 468, so thatMTF (Modulation Transfer Function) characteristics indicating sharpnessof the exposure area 468 are decreased.

On the other hand, when the micro-lens array 472 and the aperture array476 are arranged, the laser beam reflected with DMD 50 is condensed witheach micro-lens of the micro-lens array 472 according to each pixel ofDMD 50. Consequently, as shown in FIG. 28C, even if the exposure area ismagnified, the spot size of each beam spot BS can be contracted to thedesired size (for example, 10 μm×10 μm), the MTF characteristics can beprevented from decreasing to perform the fine exposure. Inclination ofthe exposure area 468 is because DMD 50 is obliquely arranged in orderto eliminate the gap between the pixels.

Even if the beam is fattened by aberration of the micro-lens, the beamcan be shaped so that the spot size on the exposed surface 56 ismaintained at constant size with the aperture, and crosstalk between theadjacent pixels can be prevented in such a manner that the beam ispassed the aperture provided corresponding to each pixel.

Furthermore, like the above-described embodiment, by using the lightsource having the high brightness for the lighting device 144, the angleof the light flux incident from the lens 458 to each micro-lens of themicro-lens array 472 is decreased, so that a part of the light flux ofthe adjacent pixel can be prevented from being incident. That is to say,a high extinction ratio can be realized.

As described above, though the exposure head and the exposure apparatusof the invention include the spatial light modulator, the exposure headand the exposure apparatus have the effect that the high speed exposurecan be performed by increasing the modulating speed of the spatial lightmodulator.

[Second Embodiment]

A second embodiment of the invention is the embodiment of the rapidprototyping apparatus in which a photo-curable resin is exposed by thelaser beam modulated with the spatial light modulator according to theimage data to shape a three-dimensional model.

(Rapid Prototyping Apparatus)

As shown in FIG. 32, the rapid prototyping apparatus according to theembodiment of the invention includes a vessel 156 whose upper surface isopened, a liquid photo-curable resin 150 is stored in the vessel 156. Aplate-shaped elevating stage 152 is arranged in the vessel 156, theelevating stage 152 is supported with a supporting portion 154 arrangedoutside the vessel 156. The supporting portion 154 is provided with anexternal thread portion 154A, and a lead screw 155 which is rotatablewith a driving motor (not shown) is bolted in the external threadportion 154A. The elevating stage 152 is elevated by rotating the leadscrew 155.

Above a liquid surface of the photo-curable resin 152 stored in thevessel 156, a box-shaped scanner 162 is arranged while its lengthwisedirection faces a short side direction of the vessel 156. A scanner 162is supported with two support arms 160 attached to both side faces ofthe short side direction. The scanner 162 is connected to a controller(not shown) which controls the scanner 162.

Each guide 158 is provided on both side faces in the lengthwisedirection of the vessel 156 respectively. The guides are equipped withlower end portions of two support arms 160 so that the support arms canbe reciprocally moved along the sub-scanning direction. A driving device(not shown) which drives the scanner 162 with the support arms 160 alongthe guides 158 is provided in the rapid prototyping apparatus.

As shown in FIG. 33, the scanner 162 includes plural (for example, 14heads) exposure heads 166 arranged in the matrix shape (for example, 3rows and 5 columns). In the embodiment, considering the width of theshort side direction of the vessel 156, four exposure heads 166 arearranged in the third row. When the specific exposure head arranged inmth row and nth column is shown, it is indicated as the exposure head166 _(mn).

An exposure area 168 generated with the exposure head 166 is a rectanglewhose short side is the sub-scanning direction. Accordingly, when thescanner 162 is moved, a band-shaped region which has been exposed (curedregion) 170 is formed in each exposure head 166 on the liquid surface ofthe photo-curable resin 152. When the exposure area which is generatedwith the specific exposure head arranged in mth row and nth column isshown, it is indicated as the exposure area 168 _(mn).

The construction, operation, and modification of each of exposure heads166 ₁₁ to 166 _(mn) are the same as those of the first embodiment.However, it is more preferable that the wave range of the GaN laserdiodes LD1 to LD7 is in the range from 350 to 420 nm. The wavelength of408 nm is particularly preferable in view of usage of the low-cost GaNlaser diode.

Similarly to the first embodiment, 600 sets of the micro-mirror column,in which the 800 pieces of the micro-mirror are arranged in the mainscanning direction, are arranged in the sub-scanning direction in DMD50, however, the control is performed so that only a part of themicro-mirror columns (for example, 800 pieces×100 columns) are drivenwith the controller.

In the rapid prototyping apparatus, the image data according to theexposure pattern of one layer is inputted to the controller (not shown)which is connected to DMD 50, and temporarily stored in the frame memoryin the controller. The image data is the data in which the density ofeach pixel constituting the image is indicated by the binary value(presence or absence of the recording of the dot).

The scanner 162 is moved at constant velocity from the upstream side tothe downstream side along the guide 158 with the driving device which isnot shown. When the movement of the scanner 162 is started, the plurallines of the image data, which is stored in the frame memory, issequentially read, and the control signal is generated in each exposurehead 166 on the basis of the image data read with the data processingportion. Each of the micro-mirrors of DMD 50 is on-off controlled ineach exposure head 166 on the basis of the generated control signal withthe mirror driving control portion.

When the laser beam is irradiated from the fiber array light source 66to DMD 50, the laser beam reflected in the case that the micro-mirror ofDMD 50 is on-state is focused on the liquid surface (exposed surface) 56of the photo-curable resin 150 with the lens systems 54 and 58. In suchway, the laser beam emitted from the fiber array light source 66 isturned on and off in each pixel and the photo-curable resin 150 isexposed in the almost same pixel unit (exposure area 168) as the numberof using pixels of DMD 50. The liquid surface of the photo-curable resin150 is sub-scanned by moving the scanner 162 at constant speed, and theband-shaped exposed region 170 is formed in each exposure head 166.

When the curing of one layer is completed with one time sub-scanning ofthe scanner 162, the scanner is returned to the home position located onthe most upstream side along the guide 158 with the driving device whichis not shown. Then, the lead screw 155 is rotated with the driving motorwhich is not shown to descend the elevating stage 152 by predeterminedquantity, the cured portion of the photo-curable resin 150 is sunk belowthe liquid surface, and the upper portion of the cured portion is filledwith the liquid photo-curable resin 150. When the image data of the nextlayer is inputted to the controller which is connected to DMD 50 and notshown, the sub-scanning of the scanner 162 is performed again. Thus, thethree-dimensional model is formed in such a manner that the exposure(curing) performed by the sub-scanning and the descent of the stage arerepeated and the cured portion is stacked.

As described above, the rapid prototyping apparatus of the embodimentincludes DMD in which 600 sets of the micro-mirror column, in which the800 pieces of the micro-mirror are arranged in the main scanningdirection, are arranged in the sub-direction, however, since the controlis performed so that only a part of the micro-mirror columns are drivenwith the controller, the modulating speed per one line is increasedcompared with the case that all the micro-mirror columns are driven.Consequently, the exposure and the shaping can be performed at highspeed.

The fiber array light source having the high brightness, in which theoutgoing end portions of the optical fiber of the incorporated laserlight source are arranged in the shape of the array, is used as thelight source irradiating DMD, so that the exposure apparatus having thehigh output, the deep focal depth, and high light density output can beobtained. Consequently, the fine shaping can be performed at high speed.Furthermore, the number of fiber light sources necessary for obtainingthe desired output is decreased by enlarging the output of each fiberlight source, so that cost-reduction of the rapid prototyping apparatuscan be achieved.

Particularly, in the embodiment, since the clad diameter of the outgoingend of the optical fiber is smaller than that of the incident end, thediameter of the light-emitting portion becomes smaller, so that the highbrightness of the fiber array light source is achieved. Consequently,the fine shaping can be realized.

(Laser Driving Method)

Each GaN laser diode including the fiber array light source may becontinuously driven or pulse-driven. Thermal diffusion is prevented bythe exposure of the pulse-driven laser beam and the high-speed and fineshaping can be performed. It is preferable that the pulse width isshorter, i.e., the pulse width of 1 psec to 100 psec is preferable, andthe pulse width of 1 psec to 300 psec is more preferable. Breakage ofthe light-outgoing end face, which is called as COD (CatastrophicOptical Damage), hardly occurs in the GaN laser diode, the GaN laserdiode has high reliability, and it is easy to realize the pulse width of1 psec to 300 psec in the GaN laser diode.

(Other Exposure Method)

Usually there is a problem that polymerization shrinkage caused by thecuring of the resin and shrinkage on curing in which the resin heated tohigh temperature with polymerization heat generated in curing aregenerated in the rapid prototyping apparatus shaping thethree-dimensional model, a shaped article is deformed by theseshrinkages accompanying the curing, and accuracy of the shaping isdecreased. In particular, when the regions including the plural pixelsare exposed simultaneously (plane exposure) to perform the shaping inshape of the plate, the shaped article is warped in downwardly convexfor the stacking direction. In order to prevent the generation of thedeformation, which is caused by the shrinkage on curing, it ispreferable that the exposure region is divided into the plural regionsand the exposure is sequentially performed.

For example, assuming that the same liquid surface of the photo-curableresin is scanned in plural times, after a borderline of the shapedarticle is exposed and the photo-curable resin is cured in the firsttime scanning, an inside region of the borderline is exposed and thephoto-curable resin is cured in the second time scanning, so that thegeneration of the deformation is prevented.

As shown in FIG. 34A, the exposure region is divided into the pluralpixels, the plural pixels are divided into a first group includingpixels 102 which are not adjacent each other and a second groupincluding pixels 104 which are not adjacent each other, and the scanningand the exposure may be performed in each group. The pixels 104 and thepixels 108 are arranged alternately so as to form a diced pattern. FIG.34A shows a part of the exposure region, for example, when the exposurehead including DMD of one million pixels is used, the exposure regioncan be divided into one million pixels according to the number of pixelsof DMD.

As shown in FIG. 34B, the pixels 104 belonging to the first group areexposed in the first time scanning, and, as shown in FIG. 34C, thepixels 108 belonging to the second group are exposed in the second timescanning. Consequently, the gap between the pixels is filled and theentire surface of the exposure region on the liquid surface of thephoto-curable resin is exposed.

The pixels of the first group, which are exposed in the first timescanning, are not adjacent each other and the pixels of the secondgroup, which are exposed in the second time scanning, are also notadjacent each other. Since the adjacent pixels are not exposedsimultaneously, the deformation caused by the shrinkage on curing is notpropagated to the adjacent pixel. That is to say, when the entireexposure region is exposed simultaneously, the deformation caused by theshrinkage on curing in increased as the deformation caused by theshrinkage on curing is propagated in the exposure region, andconsiderable deformation is generated, however, in the embodiment, theshrinkage on curing is generated only within one pixel and thedeformation caused by the shrinkage on curing is not propagated to theadjacent pixel. Consequently, the generation of the deformation isremarkably suppressed in the stacking shaped article and the fineshaping can be performed.

In the rapid prototyping apparatus of the embodiment, the liquid surfaceof the photo-curable resin can be exposed in an arbitrary pattern by theone time scanning of the scanner. Accordingly, the exposure isrelatively easily performed in each divided region by the pluralscanning.

(Photo-Curable Resin)

Usually urethane acrylate resin which is cured by photo-radicalpolymerization reaction or epoxy resin which is cured by photo-cationicpolymerization reaction is used as the liquid photo-curable resin usedfor the rapid prototyping. Sol-gel transformation type of photo-curableresin, which stays in a gel-state at ordinary temperature and transformsinto a sol-state when thermal energy is given by the laser irradiation,can be also used. In the rapid prototyping method using the sol-geltransformation type of photo-curable resin, there is an advantage that,since the exposure and the curing are performed in the shaping surfaceof not the liquid but the gel-state, the shaped article is formed in theresin in the gel-state and it is not necessary to shape a supportportion or a joint portion for supporting the shaped article.

When line exposure or area exposure in which a given region is exposedsimultaneously is performed, it is preferable that the resin in whichthermal-conductive fillers are added to the sol-gel transformation typeof photo-curable resin is used. Addition of the thermal-conductivefillers exerts thermal diffusion and the generation of thermaldeformation is prevented in the shaped article. Particularly in thesol-gel transformation type of photo-curable resin, since uniformdispersion can be performed without setting the filler unlike normalresin, the thermal diffusion can be maintained.

[Third Embodiment]

A third embodiment is the embodiment of the stacking rapid prototypingapparatus in which powder is sintered to form a sintered layer by usingthe light beam modulated with the spatial light modulator according tothe image data and the sintered layer is stacked to shape thethree-dimensional model including powder-sintered material.

(Stacking Rapid Prototyping Apparatus)

As shown in FIG. 35, the stacking rapid prototyping apparatus accordingto the embodiment of the invention includes the vessel 156 whose uppersurface is opened. The inside of the vessel 156 is divided into threeportions in the lengthwise direction with two partitions, a shapingportion 153 for producing the shaped article is arranged in the centralportion, and supplying portions 155 which supply powder 150 used for theshaping to the shaping portion 153 are arranged on both sides of theshaping portion 153.

The powder such as engineering plastic, metal, ceramics, sand, and waxcan be used as the powder 150. For example, the powder such as acomposite of acrylic acid and nylon 11, nylon 11 including beads,synthetic rubber, 316 stainless steel, 420 stainless steel, zircon sand,and silica sand can be used.

The stage 152 constituting the bottom surface of the shaping portion 153is supported with the supporting portion 154, and the stage 152 isformed to be elevated with an elevating mechanism (not shown) which isattached to the supporting portion 154. A reverse rotating roller 157which uniforms the surface of the powder 150 in the vessel 156 isattached to the upper portion of the inside of the vessel 156 while thereverse rotating roller is reciprocally movable in the sub-scanningdirection. When the stage 152 in the shaping portion 153 is descended,since the powder 150 in the shaping portion is lacked, the powder 150 issupplied from the supplying portion 155 with the reverse rotating roller157. By rotating the reverse roller 157 in the direction reverse to themoving direction, the supplied powder 150 is spread on the shapingportion 153 and the surface of the powder 150 is evened.

Above a liquid surface of the photo-curable resin 152 stored in thevessel 156, a box-shaped scanner 162 is arranged while its lengthwisedirection faces a short side direction of the vessel 156. A scanner 162is supported with two support arms 160 attached to both side faces ofthe short side direction. The scanner 162 is connected to a controller(not shown) which controls the scanner 162.

Each guide 158 is provided on both side faces in the lengthwisedirection of the vessel 156 respectively. The guides are equipped withlower end portions of two support arms 160 so that the support arms canbe reciprocally moved along the sub-scanning direction. A driving device(not shown) which drives the scanner 162 with the support arms 160 alongthe guides 158 is provided in the rapid prototyping apparatus.

As shown in FIG. 36, the scanner 162 includes plural (for example, 14heads) exposure heads 166 arranged in the matrix shape (for example, 3rows and 5 columns). In the embodiment, considering the width of theshort side direction of the vessel 156, four exposure heads 166 arearranged in the third row. When the specific exposure head arranged inmth row and nth column is shown, it is indicated as the exposure head166 _(mn).

An exposure area 168 generated with the exposure head 166 is a rectanglewhose short side is the sub-scanning direction. Accordingly, when thescanner 162 is moved, a band-shaped region which has been exposed(sintered region) 170 is formed in each exposure head 166 on the sourceof a powder 152. When the exposure area which is generated with thespecific exposure head arranged in mth row and nth column is shown, itis indicated as the exposure area 168 _(mn).

The construction, operation, and modification of each of exposure heads166 ₁₁ to 166 _(mn) are the same as those of the first embodiment.However, the laser having the oscillating wavelength except 405 nm inthe wave range from 350 to 450 nm can be also used as the GaN laserdiodes LD1 to LD7. The laser beam of the wavelength ranging from 350 to450 nm has large light absorption efficiency and is easy to be convertedinto sintering energy, so that the sintering of the powder, i.e., theshaping can be performed at high speed. It is more preferable that thewave range of the laser beam ranges from 350 to 420 nm. The wavelengthof 405 nm is particularly preferable in view of usage of the low-costGaN laser diode.

Similarly to the first embodiment, 600 sets of the micro-mirror column,in which the 800 pieces of the micro-mirror are arranged in the mainscanning direction, are arranged in the sub-scanning direction in DMD50, however, the control is performed so that only a part of themicro-mirror columns (for example, 800 pieces×100 columns) are drivenwith the controller.

In the rapid prototyping apparatus, the image data according to theexposure pattern of one layer is inputted to the controller (not shown)which is connected to DMD 50, and temporarily stored in the frame memoryin the controller. The image data is the data in which the density ofeach pixel constituting the image is indicated by the binary value(presence or absence of the recording of the dot).

The scanner 162 is moved at constant velocity from the upstream side tothe downstream side along the guide 158 with the driving device which isnot shown. When the movement of the scanner 162 is started, the plurallines of the image data, which is stored in the frame memory, issequentially read, and the control signal is generated in each exposurehead 166 on the basis of the image data read with the data processingportion. Each of the micro-mirrors of DMD 50 is on-off controlled ineach exposure head 166 on the basis of the generated control signal withthe mirror driving control portion.

When the laser beam is irradiated from the fiber array light source 66to DMD 50, the laser beam, which is reflected in the case that themicro-mirror of DMD 50 is on-state, is focused on the surface (exposedsurface) 56 of the powder 150 with the lens systems 54 and 58. In suchway, the laser beam emitted from the fiber array light source 66 isturned on and off in each pixel and the powder 150 is exposed in thealmost same pixel unit (exposure area 168) as the number of using pixelsof DMD 50. The surface of the powder 150 is sub-scanned by moving thescanner 162 at constant speed, and the band-shaped exposed region 170 isformed in each exposure head 166.

When the sintering of one layer is completed with one time sub-scanningof the scanner 162, the scanner is returned to the home position locatedon the most upstream side along the guide 158 with the driving devicewhich is not shown. When the stage 152 is descended by the predeterminedquantity with the driving mechanism which is not shown, the powder 150which is lacked is supplied from the supplying portion 155 with thestage 152 and the surface of the powder 150 is evened with the reverserotating roller 157. When the image data of the next layer is inputtedto the controller which is connected to DMD 50 and not shown, thesub-scanning of the scanner 162 is performed again. Thus, thethree-dimensional model is formed in such a manner that the exposure(sintering) performed by the sub-scanning and the descent of the stageare repeated and the sintered layer is stacked.

As described above, the stacking rapid prototyping apparatus of theembodiment includes DMD in which 600 sets of the micro-mirror column, inwhich the 800 pieces of the micro-mirror are arranged in the mainscanning direction, are arranged in the sub-scanning direction, however,since the control is performed so that only a part of the micro-mirrorcolumns are driven with the controller, the modulating speed per oneline is increased compared with the case that all the micro-mirrorcolumns are driven. Consequently, the exposure and the shaping can beperformed at high speed.

The fiber array light source having the high brightness, in which theoutgoing end portions of the optical fiber of the incorporated laserlight source are arranged in the shape of the array, is used as thelight source irradiating DMD, so that the exposure apparatus having thehigh output, the deep focal depth, and high light density output can beobtained. Consequently, the fine shaping can be performed at high speed.Furthermore, the number of fiber light sources necessary for obtainingthe desired output is decreased by enlarging the output of each fiberlight source, so that cost-reduction of the stacking rapid prototypingapparatus can be achieved.

Particularly, in the embodiment, since the clad diameter of the outgoingend of the optical fiber is smaller than that of the incident end, thediameter of the light-emitting portion becomes smaller, so that the highbrightness of the fiber array light source is achieved. Consequently,the fine shaping can be realized.

Similarly to the second embodiment, the exposure may be performed withthe pulse-driven laser beam, and the exposure may be performed while thesame sintered layer is divided into plural times.

[Fourth Embodiment]

A fourth embodiment is one which manufactures the microchip forsynthetic reaction, in which the micro channel is formed, by using theexposure apparatus according to the first embodiment.

(Microchip for Synthetic Reaction)

As shown in FIG. 37, the microchip for synthetic reaction is formed in amanner that superimposes a protecting substrate 202 on the plate-shapedsubstrate 150 made of glass or the like. A thickness of the substrate150 is usually in the range from about 0.5 mm to about 2.0 mm, thethickness of the protecting substrate 202 is usually in the range fromabout 0.1 mm to about 2.0 mm. In the protection substrate 202, inlets204 a and 204 b for pouring a reagent and an outlet 206 for exhausting areaction liquid obtained by the reaction of the reagents are provided soas to penetrate through the protecting substrate 202. A micro channel208 in which the reagent or the reaction liquid flows is provided in thesubstrate 150. The micro channel 208 is arranged so that the reagentspoured from each of the inlets 204 a and 204 b are merged at aconfluence 210 and then exhausted to the outlet 206. A channel width ofthe micro channel is several tens to several hundreds μm, and it isparticularly preferable that the channel width ranges from 10 μm to 50μm. In the micro channel having the channel width ranging from 10 μm to50 μm, channel resistance is relatively small and good size effect canbe obtained.

When the reagents are poured into each of the inlets 204 a and 204 b ofthe microchip for synthetic reaction and absorption is performed fromthe outlet 206 side, the reagents flow through the micro channel 208,and mix and react to each other at the confluence 210. This enables thedesired material to be synthesized. The obtained reaction liquid flowsthrough the micro channel 208, and the reaction liquid is exhausted fromthe outlet 206. Identification or determination of reaction product canbe performed by analysis of the reaction liquid obtained from the outlet206.

(Manufacturing Method of the Microchip)

A manufacturing method of the microchip for synthetic reaction will bedescribed below referring to FIG. 38. The manufacturing method includesan exposure process for exposing a photoresist film, a patterningprocess in which the photoresist film is partially removed andpatterned, an etching process in which the substrate is etched to formthe micro channel, and a bonding process for bonding the substrate inwhich the micro channel is formed and the protecting substrate. Eachprocess is described below.

As shown in FIG. 38A, a photoresist film 212 is formed on the substrate150 with a spin-coating method or the like, as shown in FIG. 38B, thephotoresist film 212 is exposed by following the pattern of the microchannel 208, and then, as shown in FIG. 38C, an exposure portion 214 isdissolved in the developer and removed. At this point, the micro channel208 can be formed in high accuracy by patterning the photoresist film212 in high accuracy of position. The exposure process of thephotoresist film 212 is described later.

As shown in FIG. 38D, by using the photoresist film 212 which ispatterned, the substrate 150 is etched from the surface to form themicro channel 208, as shown in FIG. 38E, the remaining photoresist film212 is removed. Though the etching of the substrate 150 can be performedwith either dry etching or wet etching, because of the micromachining,it is preferable to adopt the dry etching such as fast atom beam (FAB)etching.

As shown in FIG. 38F, through holes which will be the inlets 204 a and204 b and the outlet 206 are formed in the protecting substrate withultrasonic machining or the like. As shown in FIG. 38G, the protectingsubstrate 202 and the substrate 150 are superimposed, bonded, and fixedso that the protecting substrate 202 and the surface of the substrate150, in which the micro channel 208 is formed, are opposed each other.For example, a UV adhesive can be used for the bonding. The UV adhesiveis applied to the surface of the protecting substrate 202 with thespin-coating method or the like, the substrate 150 and the protectingsubstrate 202 are bonded, and then adhesion is performed by irradiatingan ultraviolet ray.

When the substrate 150 and the protecting substrate 202 are made ofglass, the surface of both substrates may be dissolved with hydrofluoricacid and bonded.

(Exposure of the Photoresist Film)

The exposure process of the photoresist film will be described in detailbelow. In the exposure process, by using the spatial light modulator,the laser beam having the wavelength of 350 nm to 450 nm is modulatedaccording to forming pattern data of the micro channel, and thephotoresist film 212 is digitally exposed with the modulated laser beam.In order to perform the exposure in higher accuracy, it is preferablethat the exposure is performed with the laser beam having the deep focaldepth, which is emitted from the high bright light source.

The dry film resist (DFR) used in the manufacturing process of theprinted wiring board (PWB) or an electro-deposition resist can be usedas the photoresist film 212. In DFR or the electro-deposition resist,the film can be thickened compared with the resist used in thesemiconductor manufacturing process, and the film having the thicknessfrom 10 μm to 40 μm can be formed.

The film thickness can be further thickened by laminating the plurallayers of the photoresist film. In this case, as shown in FIG. 39A, afirst photoresist film 212 a is formed and a predetermined region 214 ais exposed, and then, as shown in FIG. 39B, a second photoresist film212 b is formed on the first photoresist film 212 a and a region 214 bcorresponding to the predetermined region 214 a is exposed by using ascaling function of the digital exposure. As shown in FIG. 39C, when theexposed regions 214 a and 214 b are removed, the deep channel generatedby the resist is formed. Though the embodiment in which the two resistfilms are laminated was described, the deeper channel can be formed insuch a manner that the resist films of three or four layers arelaminated and the same position is exposed with the scaling function ofthe digital exposure.

Though the description in which the exposure is stacked at least twolayers without performing development was made, exposure may beperformed after the development such that the first layer is exposed,the development is performed, the elongation of the substrate or theswelling of the resist after the development is corrected with thedigital scaling, and then the second layer is exposed. Consequently, ashift in the pattern positioning can be corrected with high accuracy.

The deep channel generated by the resist can be formed by thickening thephotoresist film 212, and the deep channel (micro channel) can be formedin the substrate 202 with good accuracy by etching. For example, as canbe seen from FIGS. 40A and 40B, in the case that the micro channel ofthe same channel width is formed with the FAB etching, when thephotoresist film 212 is thin, the substrate 150 is easily side-etched bythe obliquely incident light. On the other hand, when the photoresistfilm 212 is thick, because of vignetting, it is difficult that theoblique light is incident to the substrate 150, and the substrate 150 ishardly side-etched. In order to perform easily the dry-etching, thesecond and third layer patterns can be corrected digitally by using theposition and the pattern width.

When the micro channel of the channel width ranging from 10 μm to 50 μmis formed, it is preferable that the thickness of the photoresist film212 ranges from 10 μm to 50 μm, and it is more preferable that thethickness ranges from 10 μm to 100 μm.

When the micro channel is formed with the wet etching using an etchingsolution, as shown in FIG. 41, the tapered aperture 216 whose sectionalshape is extended upwardly may be patterned in the photoresist film 212.Since the tapered aperture has the upwardly extended shape in section,it is easy to permeate the etching solution.

(Formation of Micro Channel)

The image data according to an exposure pattern is inputted to thecontroller which is connected to DMD 50 and not shown, and temporarilystored in the frame memory in the controller. The image data is the datadensity of each pixel constituting the image is indicated by binaryvalue (presence or absence of the recording of the dot).

The stage 152, in which the photosensitive material 150 is absorbed onthe surface, is moved at constant speed from the upstream side of thegate 160 to the downstream side along the guide 158 with the drivingdevice which is not shown. When the stage 152 passes below the gate 160,the leading end of the photosensitive material 150 is detected with thedetecting sensor 164 attached to the gate 160, the plural lines of imagedata stored in the frame memory are sequentially read, and the controlsignal is generated in each exposure head 166 on the basis of the imagedata read with the data processing portion. Each of the micro-mirrors ofDMD 50 is on-off controlled in each exposure head 166 on the basis ofthe generated control signal with the mirror driving control portion.That is to say, 600 sets of the micro-mirror column, in which the 800pieces of the micro-mirror are arranged in the main scanning direction,are arranged in the sub-scanning direction in DMD 50, and all themicro-mirror columns are used in the embodiment.

When the laser beam is irradiated from the fiber array light source 66to DMD 50, the laser beam, which is reflected in the case that themicro-mirror of the DMD 50 is on-state, is focused on the exposedsurface 56 of the photoresist film, which is formed on the substrate150, with the lens systems 54 and 58. In such way, the laser beamemitted from the fiber array light source 66 is turned on and off ineach pixel and the photoresist film is exposed in the almost same pixelunit (exposure area 168) as the number of using pixels of DMD 50. Thephotoresist film formed on the substrate 150 is sub-scanned in thedirection reverse to the stage moving direction with the scanner 162 insuch a manner that the substrate 150 is moved with the stage 152 atconstant speed, and the band-shaped exposed region 170 is formed in eachexposure head 166.

When the sub scanning of the substrate 150 with the scanner 162 isfinished and the rear end of the photosensitive material 150 is detectedwith the detecting sensor 164, the stage 152 is returned to a homeposition located on the upstream side of the gate 160 along the guide158 with the driving device which is not shown, and then moved againfrom the upstream side to down stream side of the gate 160 along theguide 158 at constant speed.

As described above, in the embodiment, since the spatial light modulatorsuch as DMD is used in the exposure process of the photoresist film, thelaser beam can be modulated in each pixel according to the formingpattern of the micro channel, and the photoresist film can be finelyexposed at high speed with the modulated laser beam. Thus, in theexposure process, the photoresist film having an arbitrary pattern canbe finely exposed at high speed, so that the micro channel having thearbitrary pattern can be finely formed at high speed through thefollowing patterning process and etching process.

Since the exposure can be performed in the arbitrary pattern, the microchannel having the complicated pattern can be easily formed. Also, sincethe exposure can be performed at high speed, the micro channel can beformed in short time on the glass substrate having the large area.Further, because of the digital exposure, it is not necessary to use amask in each pattern and the micro channel can be formed at low cost.

Since DFR or the electro-deposition resist is used as the photoresistfilm, the film can be thickened compared with the resist used in thesemiconductor manufacturing process, and the photoresist film having thethickness from 10 μm to 40 μm can be formed. Accordingly, the microchannel having the deep channel can be formed with good accuracy by theetching in a manner that thickens the photoresist film.

The film thickness can be further thickened by laminating the plurallayers of the photoresist film. In this case, the same position of themultilayered photoresist film can be exposed with the scaling functionof the digital exposure.

In the embodiment, the fiber array light source is formed with theincorporated laser light source in the exposure apparatus and the claddiameter of the outgoing end of the optical fiber is smaller than thatof the incident end, so that the diameter of the light-emitting portionbecomes smaller and the high brightness of the fiber array light sourceis achieved. Consequently, the photoresist film can be exposed morefinely with the laser beam having the deeper focal depth. For example,the exposure can be performed in the super-fine resolution such that thebeam diameter is not more than 1 μm and the resolution is not more 0.1μm, it is enough to form the micro channel having the channel width of10 μm to 50 μm.

(Fast Driving Method)

600 sets of the micro-mirror column, in which the 800 pieces of themicro-mirror are arranged in the main scanning direction, are arrangedin the sub-scanning direction in DMD 50, however, the control may beperformed so that only a part of the micro-mirror columns (for example,800 pieces×10 columns) are driven with the controller. There arelimitations of the data processing speed of DMD and decision ofmodulating speed per one line is proportional to the number of the usingpixels, so that the modulating speed per one line is increased by usingthe part of the micro-mirror columns. On the other hand, it is notnecessary to use all the pixels in the sub-scanning direction in thecase of the exposure method in which the exposure head is continuouslymoved relative to the exposure surface.

(Other Manufacturing Method of the Microchip)

Though the embodiment in which the micro channel is directly formed inthe substrate constituting the microchip was described, the microchipincluding the micro channel can be also manufactured in such a mannerthat a mold is produced by forming the micro channel in a substrate forproducing a mold and stamping or glass molding is performed by using themold.

(Microchip Including the Micro Channel)

Though the embodiment in which the microchip for synthetic reaction ismanufactured was described, the forming method of the micro channel ofthe invention can be applied to the case in which other kind ofmicrochip including the micro channel is manufactured.

A cancer diagnostics chip, a cell biochemistry chip, an environmentalmonitoring chip, a chromatographic chip, an electrophoretic chip, aprotein chip, an immune analysis chip and the like may be cited as otherkind of microchip. Though, in these chips, the forming pattern of themicro channel is different from others corresponding to the function ofeach chip, according to the forming method of the micro channel of theinvention, the etching mask can be formed by the digital exposureaccording to the forming pattern of the micro channel, so that it iseasy to correspond to wide variety of products. Also, it is easy to formthe micro channel including the plural functions. In particular, sincethe patterning of the large area can be performed in the method, theyield is improved and the invention can be the low cost forming methodof the micro channel.

The forming method of the micro channel of the invention is not limitedto the micro channel of the lob-on chip, however, the forming method ofthe micro channel of the invention can be widely applied as the methodfor forming a micro groove on the substrate.

[Fifth Embodiment]

A fifth embodiment is the embodiment of the bleaching apparatus usingthe high-output and high-bright fiber array light source, like theexposure apparatus according to the first embodiment.

(Construction of the Bleaching Apparatus)

As shown in FIG. 42, the bleaching apparatus according to the embodimentof the invention includes plural rollers 202 which carry continuouscloth 200 along a given carrying path. The bleaching apparatus alsoincludes a chemical solution tank 206 in which a chemical solution 204containing an oxidizing agent or a reducing agent is reserved, a laserirradiating portion 208 is provided on the downstream side in thecarrying direction of the chemical solution tank 206. In the irradiatingportion 208, as shown in FIG. 43, the irradiating head 500 whichpulse-irradiates the cloth 200 with the laser beam is arranged above thecloth 200 placed on the carrying path.

As shown in FIGS. 44A and 44B, the irradiating head 500 includes a fiberarray light source 506, in which many optical fibers 30 (for example,1000 fibers) are arranged in one line along the direction crossed atright angles with the sub-scanning direction, and a cylindrical lens 510which condenses the laser beam emitted from the fiber array light source506 only in the direction crossed at right angles with the arraydirection of the outgoing ends of the optical fibers 30 and focuses thelaser beam on a surface (scanning surface) 56 of the cloth 200. A moduleportion of the fiber array light source 506, to which the incident endof the optical fiber 30 is connected, is omitted in FIG. 40.

The cylindrical lens 510 has the curvature in a predetermined directionand long shape in the direction crossed at right angles with thepredetermined direction. The cylindrical lens 510 is arranged so thatthe lengthwise direction (the direction crossed at right angles with thepredetermined direction) of the cylindrical lens 510 is parallel to thearray direction of the outgoing ends of the optical fibers 30. Theirradiating optical system for uniformity using the fry-eye lens system,or the optical system for correcting light intensity distributionincluding the function, in which the light flux is widened in theportion near the optical axis and the light flux is narrowed in theportion far away from the optical axis for the array direction of thelaser outgoing end and the light is only passed through for thedirection crossed at right angles with the array direction, may be usedwith the cylindrical lens 510.

As shown in FIG. 29, the fiber array light source 506 includes manylaser modules 64, and one end of the multimode optical fiber 30 iscoupled to each laser module 64. The construction, operation, andmodification of each laser module 64 are the same as those of the firstembodiment. In each laser module 64, the coupling efficiency of thelaser beams B1 to B7 to the multimode optical fiber 30 is 0.85, wheneach output of the GaN laser diodes LD1 to LD7 is 30 mW, theincorporated laser beam B having the output of 180 mW (=30 mW×0.85×7)can be obtained for each optical fiber 31 arranged in the shape of thearray.

In the incorporated laser light beam, the laser beam having the givenpulse width can be obtain by pulse-driving each of the GaN laser diodesLD1 to LD7. The pulse irradiation of the laser beam suppresses the heatgeneration, and the damage of the fiber (damage to the cloth), which iscaused by the heat, is prevented.

It is preferable that each of peak power ranges from 300 mW to 3 W. Whenthe peak power is 300 mW, the pulse width ranges from 10 nsec to 10μsec, it is preferable that the number of pulses ranges from 10⁴ to 10⁷.In this case, duty is about 10%. When the peak power is 3 W, the pulsewidth ranges from 1 nsec to 1 μsec, it is preferable that the number ofpulses ranges from 10⁴ to 10⁷. In this case, duty is about 1.0%.

As described above, the breakage of the light-outgoing end face, whichis called as COD (Catastrophic Optical Damage), hardly occurs in the GaNlaser diode, the GaN laser diode has high reliability, and the high peakpower can be realized.

(Operation of the Bleaching Apparatus)

The operation of the above-described bleaching apparatus will bedescribed below.

When the cloth 200 which has experienced a refining process removingimpurities such as oil content deposited to the fiber and a desizingprocess removing fabric size is supplied to the bleaching apparatus, thecloth 200 is carried in toward the direction of an arrow A with rotatingcarrying roller 202, and dipped into the chemical solution 204 in thechemical solution tank 206. It is preferable that dipping time rangesfrom 0.1 to 1 hour.

The chemical solution 204 contains the oxidizing agent or the reducingagent. Peroxide such as hydrogen peroxide (H₂O₂), sodium perborate(NaBO₃.4H₂O), and potassium permanganate (KMnO₄), or chlorine compoundsuch as a bleaching powder (CaCl.ClO), sodium hypochlorite (NaClO), andsodium chlorite (Na₂ClO₂) can be used as the oxidizing agent.Hydrosulfite (Na2S2O4), sodium tetrahydroborate (NaBH4) or the like canbe used as the reducing agent. In these chemicals, the tetrahydroboratewhich has weak oxidation-reduction action is particularly preferable inview of suppression of the damage of the fiber.

Water or lower alcohol such as ethanol and methanol can be used as asolvent. It is preferable that concentration of the oxidizing agent orthe reducing agent ranges from 1% to 10%. An activator for activatingthe oxidizing agent and the reducing agent may be appropriately added tothe chemical solution 204.

Then, the cloth 200 taken out from the chemical solution tank 206 issupplied to the laser irradiating portion 208 while the chemicalsolution 204 is impregnated. In the laser irradiating portion 208, thelaser beam emitted from the fiber array light source 506 of theirradiating head 500 is condensed only in the direction crossed at rightangles with the array direction of the outgoing ends of the opticalfibers 30 with the cylindrical lens 510, and focused on the surface 56of the cloth 200 in the shape of the line. The cylindrical lens 510functions as a magnifying optical system which magnifies the beamdiameter, e.g., the magnification of three times in the short axialdirection and one time in the long axial direction. The cloth 200 iscarried at constant speed, and sub-scanned in the direction reverse tothe carrying direction with a line beam 502 from the irradiating head500.

By irradiating the cloth in which the chemical solution is impregnatedwith the laser beam, color content deposited to the fiber and theoxidizing agent or the reducing agent in the chemical solution 204 areactivated, reactivity between the color content and the agent isincreased, and the good bleaching effect can be obtained. In order toprevent the damage of the fiber, which is caused by the heat, and obtainactivation effect, the wavelength of the irradiating laser beam rangesfrom 350 nm to 450 nm, it is more preferable that the wavelength rangesfrom 400 nm to 415 nm. On the other hand, when the reactivity of theoxidizing agent or the reducing agent is high, it is preferable that thewavelength is not lower than 400 nm. In the wavelength of not lower than400 nm, load to the optical system is small and it is easy to increasethe output of the laser diode.

Light density on the surface of the cloth 200 is calculated. In theincorporated laser light source of the irradiating head, when eachoutput of the GaN laser diodes LD1 to LD7 is 30 mW, the incorporatedlaser beam B having the output of 180 mW can be obtained for each of theoptical fibers 30 which are arranged in the shape of the array.Accordingly, in the case of the fiber array light source in which 1000multimode optical fibers 30 are arranged in one line, the output isabout 180 W in the continuous operation at the laser outgoing portion68.

In the laser outgoing portion 68 of the fiber array light source 506,high-bright light-emitting points are arranged in one line along themain scanning direction. Since the fiber light source in the relatedart, in which the laser beam from the single laser diode is coupled toone optical fiber, is low output, the desired output can not be obtainedunless many columns of the fiber light source are arranged, however,since the incorporated laser light source used in the embodiment is highoutput, few columns, e.g., even only one column can obtain the desiredoutput.

When the step index type of optical fiber, in which the clad diameter is125 μm, the core diameter is 50 μm, and NA is 0.2, is used as themultimode optical fiber 30, the beam diameter of the laser outgoingportion is 50 μm×125 μm. When the beam diameter is magnified three timesin the short axial direction and one time in the long axial direction,the area of the irradiating area 506 becomes 150 μm×125 μm.

In the bleaching adopting the laser assist, generally it is necessarythat the high light density ranges from 2000 mJ/cm² to 20000 mJ/cm²,however, in the embodiment, the light density of the range can be easilyrealized by changing appropriately the number of fibers which arearrayed and the number of incorporated laser beams. Assuming that thelight density on the exposure surface, which is required for thebleaching, is 10000 mJ/cm², when the pulse irradiation is performed onconditions that the peak power of the GaN laser diodes LD1 to LD7 is 3W, the pulse width is 100 nsec, the pulse number per second is 105, andthe duty is 1%, the light density per pulse on the exposure surface is10 mJ/cm², the exposure can be performed as fast as 1.4 cm/s.

On the other hand, when the excimer laser is used instead of theincorporated laser light source of the GaN laser diode, since therepeating frequency is decreased, more than about ten times speed isrequired for the exposure of the same area.

As described above, in the bleaching apparatus of the embodiment, byusing the fiber array light source in which the incorporated laser lightsource having the high output and the high brightness are arrayed, thecloth impregnated with the chemical solution is pulse-irradiated withthe laser beam, the high energy density can be obtained on the surfaceof the cloth. Consequently, at least one of the chemical solution andthe color content is activated, the bleaching reaction is promoted, andhigh bleaching effect can be obtained. The duty of the laser pulse is1%, so that the heat generation can be suppressed and the damage of thefiber can be prevented.

In the bleaching apparatus of the embodiment, since the incorporatedlaser light source is used for the laser irradiating portion, comparedwith the bleaching apparatus using the excimer laser, the bleachingapparatus of the embodiment can be pulse-driven in arbitrary repeatingfrequency and pulse width, the bleaching can be performed as fast asseveral times by setting the repeating frequency at a high value.Compared with the bleaching apparatus using the excimer laser, theenergy efficiency is as high as 10% to 20%, the maintenance is easy, andit is low-cost.

In particular, since the GaN laser diode is covalent bond, the breakageof the light-outgoing end face, which is called as COD (CatastrophicOptical Damage), hardly occurs in the GaN laser diode, the GaN laserdiode has high reliability, and the high peak power can be realized. Forexample, the high peak power of 3 W can be realized on conditions thatthe pulse width is 100 nsec and the duty is 1%. In this case, theaverage output is 30 mW.

In the bleaching apparatus of the embodiment, the line beam can beeasily obtained by arraying the optical fibers of the fiber array lightsource. Since fiber products are usually formed in the shape of thecontinuous sheet, it is rational that the laser irradiation is performedwith the line beam which is focused in the short axial direction andended in the long axial direction. The line beam length can be extendedby increasing the number of optical fibers which are arrayed, whileenergy strength and uniformity are maintained. Further, since the laserbeam having the wavelength of 350 to 450 nm is used, it is not necessaryto generate the line beam with the optical system using a specialmaterial for the ultraviolet ray, and it is low-cost.

(Multi-Head)

Though the embodiment which is provided with the laser irradiatingportion including the single irradiating head was described, when thelength in the long axial direction of the line beam is short, the pluralirradiating heads may be arranged in the long axial direction.

(Laser Diode)

Though the embodiment in which the GaN laser diode having theoscillating wavelength of 350 nm to 450 nm, in which the increase in theoutput is expected in near future, is used as the laser diode wasdescribed, the laser diode is not limited to the GaN laser diode. Forexample, a nitride laser diode containing III-group element such as Al,Ga, and In and nitrogen can be used. The nitride laser diode may includeany composition expressed by Al_(x)Ga_(y)In_(1−x−y)N (x+y=<1). The laserdiode having the oscillating wavelength of 200 nm to 450 nm can beobtained by changing the composition.

(Other Embodiment of the Magnifying Optical System)

As shown in FIGS. 45A and 45B, the irradiating head 500 may include thefiber array light source 506, in which many optical fibers 30 (forexample, 1000 fibers) are arranged in one line along the directioncrossed at right angles with the sub-scanning direction, a firstcylindrical lens 512 which condenses the laser beam emitted from thefiber array light source 506 only in the direction crossed at rightangles with the array direction of the outgoing ends of the opticalfibers 30, and a second cylindrical lens 514 which condenses the laserbeam condensed in the direction crossed at right angles with the arraydirection of the outgoing ends of the optical fibers 30 only in thearray direction and focuses the laser beam on the surface (scanningsurface) 56 of the cloth 200.

The first cylindrical lens 512 has the curvature in a predetermineddirection and long shape in the direction crossed at right angles withthe predetermined direction. The first cylindrical lens 512 is arrangedso that the lengthwise direction (the direction crossed at right angleswith the predetermined direction) of the first cylindrical lens 512 isparallel to the array direction of the outgoing ends of the opticalfibers 30. The second cylindrical lens 514 has the curvature in thepredetermined direction and long shape in the predetermined direction.The cylindrical lens 510 is arranged so that the curvature direction(the predetermined direction) of the second cylindrical lens 514 isparallel to the array direction of the outgoing ends of the opticalfibers 30.

In the irradiating head, the laser beam emitted from the fiber arraylight source 506 is condensed in the direction crossed at right angleswith the array direction of the outgoing ends of the optical fiber 30 bythe first cylindrical lens 512, condensed in the array direction of theoutgoing ends of the optical fibers 30, and focused on the scanningsurface 56 in the shape of the line.

For example, the cylindrical lenses 512 and 514 function as themagnifying optical system which magnifies the beam diameter three timesin the short axial direction and ten times in the log axial direction.In FIG. 42, the cloth 200 is carried at constant speed, and sub-scannedin the direction reverse to the carrying direction with the line beamfrom the irradiating head 500. Thus, the wide exposure surface can beexposed in such a manner that the beam of the fiber array light sourceis magnified with the optical system. Also, by magnifying the beam, thedeeper focal depth can be obtained and the cloth carried at high speedcan be irradiated uniformly.

The light density on the surface is calculated here. When the multimodelaser whose peak power is 6 W is used for the incorporated laser lightsource of the irradiating head, the incorporated laser beam B whose peakpower is 36 W can be obtained with the seven laser diodes. Accordingly,in the case of the fiber array light source in which 1000 multimodeoptical fibers 30 are arranged in one line, the peak power is about 36kW at the laser outgoing portion 68.

When the step index type of optical fiber, in which the clad diameter is125 μm, the core diameter is 50 μm, and NA is 0.2, is used as themultimode optical fiber 30, the beam diameter of the laser outgoingportion is 50 μm×125 μm. When the beam diameter is magnified three timesin the short axial direction and ten times in the long axial direction,the area of the irradiating area 506 becomes 150 μm×1250 μm. When thepulse irradiation is performed on conditions that the peak power is 6 W,the pulse width is 100 nsec, the duty is 1%, and the pulse number persecond is 105, the light density per pulse on the exposure surface is 2mJ/cm². Estimating that the loss in the optical system is about 80%, thelight density per pulse on the exposure surface is 1.5 mJ/cm².Accordingly, when the exposure is performed at the light density of10000 mJ/cm², the exposure of the cloth having the width of 1.25 m canbe performed as fast as 0.2 cm/s.

(Modification of Optical Fiber)

Though the embodiment in which the uniform optical fiber whose claddiameter is 125 μm is used as the incorporated laser light source wasdescribed, the clad diameter of the outgoing end of the optical fibercan be formed to be smaller than that of the incident end, like thefirst embodiment. The diameter of the light-emitting portion becomessmaller by decreasing the clad diameter of the outgoing end of theoptical fiber, so that the high brightness of the fiber array lightsource is achieved.

(Modification of the Incorporated Laser Light Source)

In the incorporated laser light source utilizing the laser array havingthe multi-step construction, which is shown in FIGS. 24A and 24B,particularly the high output can be achieved by the multi-steparrangement of the multi-cavity laser and the array of the collimatorlenses. Since the brighter fiber array light source or bundle fiberlight source can be formed by using the incorporated laser light source,it is particularly preferable for the fiber light source constitutingthe laser light source of the irradiating head of the embodiment.

In this case, the light density on the surface is calculated. Assumingthat the multi transverse mode chip is used as the incorporated laserlight source of the irradiating head and peak power per onelight-emitting point is 6 W, the incorporated laser beam whose peakpower is 103 W can be obtained with the twenty laser diodes.Accordingly, in the case of the fiber array light source in which 1750multimode optical fibers are arranged in one line, the peak power isabout 180 kW at the laser outgoing portion.

When the same optical fiber is used as the multimode optical fiber, thebeam diameter of the laser outgoing portion is 50 μm×220 μm. When thebeam diameter is magnified three times in the short axial direction andten times in the long axial direction, the area of the irradiating area506 becomes 150 μm×2200 μm. When the pulse irradiation is performed onthe surface of the cloth on conditions that the peak power is 6 W, thepulse width is 100 nsec, the duty is 1%, and the pulse number per secondis 105, the light density per pulse on the exposure surface is 10mJ/cm². Estimating that the loss in the optical system is about 80%, thelight density per pulse on the exposure surface is 8 mJ/cm².Accordingly, when the exposure is performed at the light density of10000 mJ/cm², the exposure of the cloth having the width of 2.2 m can beperformed as fast as 1.2 cm/s.

1. A rapid prototyping apparatus comprising: an exposure head includinga forming tank which stores a photo-curable resin, a support which iselevatably provided in the forming tank for supporting a formed article,a laser device which irradiates a laser beam, a spatial light modulatorin which plural pixel portions, in which a light modulation state ischanged according to respective control signals, are two-dimensionallyarranged on a substrate and which modulates the laser beam irradiatedfrom the laser device, control means which controls each of a number ofthe plural pixel portions that is fewer than a total number of the pixelportions arranged on the substrate, using the control signals generatedaccording to exposure information, and an optical system which focusesthe laser beam modulated at each pixel portion on a liquid surface ofthe photo-curable resin stored in the forming tank; and moving meanswhich relatively moves the exposure head with respect to the liquidsurface of the photo-curable resin.
 2. The rapid prototyping apparatusof claim 1, wherein the laser device comprises a plurality of fiberlight sources which irradiates the laser beam which is incorporated andincident to an incident end of the optical fiber from an outgoing end ofthe optical fiber, and includes a fiber array light source in whichlight-emitting points at the outgoing end of the plurality of fiberlight sources are arranged in the shape of an array, or a fiber bundlelight source in which light-emitting points at the outgoing end arearranged in the shape of a bundle.
 3. A rapid prototyping apparatuscomprising: an exposure head including a forming tank which stores apowder to be sintered by light irradiation, a support which iselevatably provided in the shaping tank for supporting a formed article,a laser device which irradiates a laser beam, a spatial light modulatorin which plural pixel portions, at which a light modulation state ischanged according to respective control signals, are two-dimensionallyarranged on a substrate and which modulates the laser beam irradiatedfrom the laser device, control means which controls each of a number ofthe plural pixel portions that is fewer than a total number of the pixelportions arranged on the substrate, using the control signals generatedaccording to exposure information, and an optical system which focusesthe laser beam modulated at each pixel portion on a surface of thepowder stored in the forming tank; and moving means which relativelymoves the exposure head with respect to the surface of the powder. 4.The rapid prototyping apparatus of claim 3, wherein the laser devicecomprises a plurality of fiber light sources which irradiates the laserbeam which is incorporated and incident to an incident end of theoptical fiber from an outgoing end of the optical fiber, and includes afiber array light source in which light-emitting points at the outgoingend of the plurality of fiber light sources are arranged in the shape ofan array, or a fiber bundle light source in which light-emitting pointsat the outgoing end are arranged in the shape of a bundle.
 5. The rapidprototyping apparatus of claim 3, wherein the laser device ispulse-driven.
 6. The rapid prototyping apparatus of claim 5, wherein thelaser device is pulse-driven with a pulse width of 1 psec to 100 nsec.